bluuebunny/crossref_metadata_2025 huggingface dataset:
Tachykinin Systems in the Spinal Cord and Basal Ganglia: Influence of Neonatal Capsaicin Treatment or Dopaminergic Intervention on Levels of Peptides, Substance P–Encoding mRNAs, and Substance P Receptor mRNA
Authors: Sivam S. P. , Krause J. E.
Published: July 2010

Abstract:The aim of the study was to test whether the synthesis of substance P (SP) and that of its receptor (also known as NK1 receptor) are coordinately regulated after chronic pharmacologic intervention in two neural systems, the spinal cord and basal ganglia. In one set of experiments, capsaicin was administered subcutaneously during the early postnatal period (day 3 after birth) to induce degeneration of afferent sensory neurons in the spinal cord. In the other set of experiments, interruption of dopaminergic transmission was achieved by two methods: (a) The neurotoxin 6‐hydroxydopamine was used to denervate dopaminergic neurons during the early postnatal period, and (b) haloperidol was used in adult animals to block dopaminergic transmission by receptor blockade. The spinal cord, striatum, or both were used for the quantification of tachykinin [SP and neurokinin A (NKA)] and opioid peptides [[Met5]‐enkephalin (ME) and dynorphin A (1–8) (DYN)] by radioimmunoassays. The abundance of total SP‐encoding preprotachykinin (PPT) mRNA and SP receptor (SPR) mRNA in spinal cord (C5 to T1 segments), striatum, or microdissected substantia nigra was determined by northern blot or solution hybridization analysis. Amines and their acid metabolites were quantified by HPLC. Capsaicin administration (subcutaneously) during the early postnatal period increased latency in a hot‐plate test, decreased SP and NKA levels, increased levels of PPT mRNAs, and did not affect SPR mRNA levels in the spinal cord. Intraspinal SP systems may attempt to compensate for the loss of afferent SP input, whereas spinal cord receptor mRNA levels do not appear to be altered. Neonatal dopaminergic denervation or haloperidol blockade of dopamine receptors in adult rats decreased PPT mRNA levels in the striatum as previously reported but did not alter the abundance of SPR mRNA in the striatum or substantia nigra. The presence of SPR mRNA levels in microdissected substantia nigra and the lack of alteration in its levels as a consequence of dopamine denervation suggest that the receptor is expressed within nondopaminergic neurons, possibly GABAergic neurons. In both spinal cord and basal ganglia systems, regardless of increases or decreases in SP or SP‐encoding mRNA levels, SPR mRNA levels were not altered. We conclude that the regulation of the presynaptic biosynthesis of SP and the postsynaptic regulation of the SPR mRNA can be modulated independently of each other in spinal cord and basal ganglia SP systems.
Nicotinic Cholinergic Regulation of Tyrosine Hydroxylase Gene Expression and Catecholamine Synthesis in Isolated Bovine Adrenal Chromaffin Cells
Authors: Craviso Gale L. , Hemelt Virginia B. , Waymire Jack C.
Published: July 2010

Abstract:Isolated bovine adrenal chromaffin cells were used to study the nicotinic regulation of tyrosine hydroxylase (TH) gene expression. Continuous exposure of the cells to carbachol or the nicotinic receptor agonist 1,1‐dimethyl‐4‐phenylpiperazinium (DMPP) produces a time‐ and concentration‐dependent increase in TH enzyme activity, whereas muscarine has no effect. DMPP at 1 μM(EC50= 0.3 μM) elicits a two‐ to threefold elevation of both TH activity and TH immunoreactive protein level after 3–5 days in the presence of 2.5 mMcalcium; the increase in enzyme levels is significantly less at lower extracellular calcium levels. The rate of hydroxylation of tyrosine to dopamine (DA) in intact cells, an index of endogenous TH activity, increases in parallel with the rise in TH levels. The TH mRNA level is elevated before the increase in protein levels. As determined by nuclear run‐on assays, TH gene transcription is stimulated two‐ to threefold within 30 min of addition of 1 μMDMPP to the cells; transcription returns to basal levels by 2 h. Nitrendipine (20 μM) blocks the stimulation of transcription by DMPP. Pretreatment of the cells with cycloheximide (5 μM) does not prevent the DMPP stimulation of transcription. Forskolin (10 μM) also increases TH transcription (fourfold in 15 min) by a mechanism that is not blocked by cycloheximide. These results show that nicotinic receptor stimulation increases TH mRNA synthesis, TH protein levels, and TH activity in a calcium‐dependent manner. Furthermore, the nicotinic influence on TH gene expression does not appear to require the synthesis of a protein factor for its effects. That in situ DA synthesis rates are elevated consequent to the rise in TH levels demonstrates that TH induction serves as a mechanism for enhancing the catecholamine‐synthesizing capacity of the chromaffin cell on a long‐term basis.
Differential Sensitivity of the Short and Long Human Dopamine D2Receptor Subtypes to Protein Kinase C
Authors: Liu Ya Fang , Civelli Olivier , Grandy David K. , Albert Paul R.
Published: July 2010

Abstract:The human dopamine D2L(long form) and D2S(short form) receptors were expressed separately in mouse Ltk−fibroblast cells to investigate whether there is a difference in transmembrane signaling of these D2receptors. Both receptors induced two signals, a phosphatidylinositol‐linked mobilization of intracellular calcium and an inhibition of cyclic adenosine 3′‐5’monophosphate (cAMP) accumulation, each with similar response magnitudes and identical pharmacology. Both calcium and cAMP signals were sensitive to pretreatment with pertussis toxin (PTX), indicating mediation by coupling to Gi/Goproteins. However, the two forms of D2receptor were distinguished by acute prior activation of protein kinase C (PKC) with 12‐O‐tetradecanoyl 4β‐phorbol 13‐acetate (TPA): TPA blocked the D2S‐mediated increase in cytosolic free calcium concentration ([Ca2+]i) in a concentration‐dependent manner (between 10 nMand 1 μM), whereas the D2Lreceptor‐induced increase in [Ca2+]iwas resistant to TPA and was only partially (60%) inhibited by 100 μMTPA. By contrast, TPA did not alter the inhibition of cAMP accumulation induced by activation of either D2Sor D2Lreceptors. We conclude that, in the L cell system, prior activation of PKC differentially modulates the transmembrane signaling of the D2Land D2Sreceptors, preferentially inhibiting the D2Sreceptor‐mediated calcium signal but not altering the dopamine‐induced inhibitory cAMP signal of either receptor subtype.
An Alternative Secretase Cleavage Produces Soluble Alzheimer Amyloid Precursor Protein Containing a Potentially Amyloidogenic Sequence
Authors: Anderson John P. , Chen Yu , Kim Kwang S. , Robakis Nikolaos K.
Published: July 2010

Abstract: Cell culture studies have shown that the Alzheimer amyloid precursor protein (APP) is secreted after full‐length APP is cleaved by a putative secretase at the Lys16‐Leu17 bond (secretase cleavage I) of the amyloid peptide sequence. Because this cleavage event is incompatible with amyloid production, it has been assumed that secreted APP cannot serve as a precursor of the amyloid depositions observed in Alzheimer's disease. Here we show that in neuronally differentiated PC12 cells and human kidney 293 cell cultures a portion of the secreted extracytoplasmic APP reacted specifically with both a monoclonal antibody recognizing amyloid protein residues Leu17‐Val24 and a polyclonal antiserum directed against amyloid protein residues Ala21‐Lys28. Furthermore, this APP failed to react with antisera recognizing the cytoplasmic domain of the full‐length protein. These data indicate the presence of an alternative APP secretase cleavage site (secretase cleavage II), C‐terminal to the predominant secretase cleavage I. Depending on the exact location of cleavage site II, potentially amyloidogenic secreted APP species may be produced.
Sphingosine, W‐7, and Trifluoperazine Inhibit the Elevation in Cytosolic Calcium Induced by High K+Depolarization in Synaptosomes
Authors: Sitges Maria , Talamo Barbara R.
Published: July 2010

Abstract:A possible role for protein kinases in the regulation of free cytosolic Ca2+levels in nerve endings was investigated by testing the effect of several kinase inhibitors on the increase in cytosolic Ca2+(monitored with the Ca2+‐sensitive dye fura‐2) induced by depolarization with 15 or 30mMK+. The ability of various drugs to inhibit the cytosolic Ca2+response appeared to correlate with their reported mechanism of action in inhibiting protein kinases. W‐7 and trifluoperazine, drugs reported to inhibit calmodulin‐dependent events, were effective inhibitors of the increase in cytosolic Ca2+induced by high K+depolarization, as was sphingosine, a drug that inhibits protein kinase C by binding to the regulatory site, but which also inhibits calcium/calmodulin kinase. On the other hand, drugs that inhibit protein kinases by binding to the catalytic site, such as H‐7 (1m/W), staurosporine (1μM), and K252a(1μM), were ineffective. Activation of protein kinase C, which is blocked by each of these drugs, does not appear to be essential to the maintenance of elevated cytosolic Ca2+in depolarized synaptosomes. All of the drugs, including sphingosine, that functionally inhibit the depolarization‐induced elevation in cytosolic Ca2+have in common the ability to bind to calmodulin. Because the drugs that inhibit protein kinases by competing with ATP binding at the active catalytic site did not block the response in this system, we suggest that a calmodulin or a calmodulin‐like binding site participates in the regulation of Ca2+increases after depolarization.
Purification and Chemical Characterization of β‐Trace Protein from Human Cerebrospinal Fluid: Its Identification as Prostaglandin D Synthase
Authors: Hoffmann Andrea , Conradt Harald S. , Gross Gerhard , Nimtz Manfred , Lottspeich Friedrich , Wurster Ulrich
Published: July 2010

Abstract: β‐Trace protein from pooled human CSF was purified to homogeneity. An apparent molecular mass of 23–29 kDa was determined for the polypeptide on sodium dodecyl sulfate‐polyacrylamide gel electrophoresis. Amino‐terminal sequencing of the polypeptide yielded the unique amino acid sequence APEAQVSVQPNFQQDKFLGRWFSA24. Alignment of amino acid sequences obtained from tryptic peptides with the sequence previously deduced from a cDNA clone isolated by other investigators allowed the identification of β‐trace protein as prostaglandin D synthase [prostaglandin‐H2 D‐isomerase; (5Z, 13E)‐(15S)‐9α, 11 a‐epidioxy‐15‐hydroxyprosta‐5,13‐dienoate D‐isomerase; EC 5.3.99.2]. A conservative amino acid exchange (The instead of Ser) was detected at amino acid position 154 of the β‐trace polypeptide chain in the corresponding tryptic peptide. The two N‐glycosylation sites of the polypeptide were shown to be almost quantitatively occupied by carbohydrate. Carbohydrate compositional as well as methylation analysis indicated that Asn29and Asn56 bear exclusively complex‐type oligosaccharide structures (partially sialylated with α2–3‐ and/or α2–6‐linked N‐acetylneuraminic acid) that are almost quantitatively α1‐6 fucosylated at the proximal N‐acetylglucosamine; ∼70% of these molecules contain a bisecting N‐acetylglucosamine. Agalacto structures as well as those with a peripheral fucose are also present.
Endogenous Noradrenaline Activates α2‐Adrenoceptors on Serotonergic Nerve Endings in Human and Rat Neocortex
Authors: Feuerstein T. J. , Mutschler A. , Lupp A. , Van Velthoven V. , Schlicker E. , Göthert M.
Published: July 2010

Abstract:Slices from human neocortex preincubated with [3H]serotonin ([3H]5‐HT) were superfused and stimulated electrically to investigate whether the α2‐adrenoceptors on serotonergic terminals can be stimulated by endogenous noradrenaline (NA) released from neighboring noradrenergic fibers. The stimulation‐evoked3H overflow, representing action potential‐induced, exocytotic release of 5‐HT, was depressed by the NA uptake blocker (+)‐oxaprotiline. Rauwolscine (a mixed α2‐adrenoceptor antagonist/5‐HT autoreceptor agonist) or phentolamine [a combined α‐ adrenoceptor/5‐HT autoreceptor antagonist; the latter drug in the presence of (+)‐oxaprotiline] enhanced the release when the 5‐HT autoreceptors had previously been blocked by metitepine. Under hypothermia the release of 5‐HT was found to be decreased and that of NA to be increased; under these conditions idazoxan (an α2‐adrenoceptor antagonist) enhanced the release of 5‐HT. In neocortex slices from rats (+)‐oxaprotiline similarly depressed the release of 5‐HT (measured with the same methods) as in human tissue. When rats were pretreated with 6‐hydroxydopamine, the inhibitory effect of exogenous NA on 5‐HT release was increased, and in slices from rats pretreated with desipramine, it was decreased. In conclusion, α2‐heteroreceptors can be activated by endogenous NA released from neighboring noradrenergic fibers. Because regulatory processes analogous to those in rats probably occur in humans as well, an up‐ or down‐regulation of α2‐ heteroreceptors in depressed patients with a (pathological) decrease or a (therapeutic) enhancement of the noradrenergic neurotransmission may also be assumed to occur.
Species Differences in Dopamine Transporters: Postmortem Changes and Glycosylation Differences
Authors: Patel Amrat , Uhl George , Kuhar Michael J.
Published: July 2010

Abstract:The apparent molecular masses of photoaffinity‐labeled dopamine transporters (DATs) from rat, human, dog, and primate kidney COS cells expressing the ratDAT1cDNA differ. Sequences predicted from cDNA cloning reveal only one amino acid difference between the length of the rat and human DAT but one less site for potential N‐linked glycosylation in the human DAT. Possible posttranslational and postmortem bases for species differences in DAT molecular mass were explored. Rat DAT proteins from striata subjected to ∼5 h of postmortem delay modeled after the human postmortem delay process revealed small but consistent losses in apparent molecular mass and in cocaine analogue binding; the DAT molecular mass displayed no further losses for up to 30 h of model postmortem treatment. Degradative postmortem changes could thus contribute to molecular mass differences between rat and human DATs. Neuraminidase treatment reduced the apparent molecular mass of native rat DAT but not that of the rat DAT expressed in COS cells, suggesting that the sugars added to the DAT expressed in COS cells were different than those added to the rat brain striatal transporter. These differences could account for the somewhat higherKmvalues for expressed DAT cDNA in COS cells when compared with the wild‐type striatal transporter. These results are in accord with the differences in number of predicted N‐linked glycosylation sites between rat and human DATs and with cell‐type specificity in transporter posttranslational processing.
Potentiation of45Ca Uptake and Acute Toxicity Mediated by theN‐Methyl‐D‐Aspartate Receptor: The Effect of Metal Binding Agents and Transition Metal Ions
Authors: Eimerl Sara , Schramm Michael
Published: July 2010

Abstract:The activities mediated by theN‐methyl‐D‐aspartate (NMDA) receptor were studied in cultured rat cerebellar granule cells. Micromolar concentrations of the metal binding compounds, EDTA, cysteine, and histidine, as well as serum albumin strongly potentiated receptor activity in the presence of millimolar concentrations of Ca2+and Mg2+. The findings indicated that these agents remove an endogenous metal, probably Zn2+, which attenuates NMDA receptor‐mediated45Ca uptake and toxicity. Several added metal ions were therefore tested at low micromolar concentrations. Zn2+was found to be the most potent inhibitor of NMDA‐induced45Ca uptake, followed by Cu2+and Fe2+. Co2+, Cd2+, Fe3+, and AI3+had no significant effect, whereas Ni2+potentiated the45Ca uptake but inhibited at much higher concentrations. The potentiating agents that remove the endogenous metal had a particularly dramatic effect in the presence of Mg2+, the voltage‐dependent suppressor of the NMDA receptor. Mg2+also played an important role in the inhibitory effect of added Zn2+. Much lower concentrations of Zn2+were needed to achieve inhibition of NMDA‐induced45Ca uptake in the presence of Mg2+. Under a variety of conditions, a very good correlation was found between NMDA receptor‐mediated45Ca uptake and the magnitude of acute neurotoxicity.
Histamine Evokes Greater Increases in Phosphatidylinositol Metabolism and Catecholamine Secretion in Epinephrine‐Containing than in Norepinephrine‐Containing Chromaffin Cells
Authors: Choi Alice Y. , Cahill Anne L. , Perry Bruce D. , Perlman Robert L.
Published: July 2010

Abstract:Chromaffin cells have H1histamine receptors. Histamine, acting at these receptors, increases the metabolism of inositol‐containing phospholipids and stimulates catecholamine secretion from Chromaffin cells. We have investigated the effects of histamine and other agents on the accumulation of inositol monophosphate (InsP1) and catecholamine secretion in purified cultures of norepinephrine‐containing and epinephrine‐containing bovine Chromaffin cells. Histamine‐stimulated InsP, accumulation in epinephrine cells was three times greater than that in norepinephrine cells. In contrast, bradykinin caused roughly equivalent increases in InsP1accumulation in the two Chromaffin cell subtypes. Histamine‐stimulated catecholamine secretion was also greater in epinephrine cells than in norepinephrine cells, whereas high K+, bradykinin, phorbol 12, 13‐dibutyrate, and angiotensin II all caused greater secretion from norepinephrine cells than from epinephrine cells. The density of H1receptors in epinephrine cells was approximately three times greater than that in norepinephrine cells. The greater density of H1receptors on epinephrine cells may account for the greater effects of histamine on InsP1accumulation and catecholamine secretion in these cells.
Identification of a Chymotrypsin‐Like Mast Cell Protease in Rat Brain Capable of Generating the N‐Terminus of the Alzheimer Amyloid β‐Protein
Authors: Nelson Robert B. , Siman Robert , Iqbal Mohamed A. , Potter Huntington
Published: July 2010

Abstract: Cleavage after Met596 of the β‐amyloid precursor protein to generate the N‐terminus of β‐protein indicates the activity of a protease having chymotrypsin‐like specificity. A chymotrypsin‐like protease is further implicated in Alzheimer's disease by the increased synthesis of the protease inhibitor α1‐antichymotrypsin in pathologically affected brain regions and by the presence in the amyloid deposits of inactivated forms of α1‐antichymotrypsin (indicating irreversible binding to a target chymotrypsin‐like protease). In the present report, we have purified from rat brain a chymotrypsin‐like protease that (a) binds with high affinity to human α1‐antichymotrypsin, (b) proteolytically generates a β‐protein‐containing C‐terminal fragment from full‐length recombinant human β‐amyloid precursor protein, and (c) selectively cleaves methoxysuccinyl‐Glu‐Val‐Lys‐Met‐p‐nitroanilide (a substrate modeling the protease recognition domain for the β‐protein N‐terminal cleavage site). Amino acid sequences of tryptic fragments of the purified rat brain chymotrypsin‐like protease indicate an identity with rat mast cell protease I. Moreover, the ontogeny and compartmentalization of rat brain chymotrypsin‐like protease are consistent with those of connective tissue‐type mast cells in the meningeal and intracortical perivasculature. Because these areas in human brain form extensive β‐amyloid deposits in Alzheimer's disease, Down's syndrome, and hereditary cerebral hemorrhage with amyloidosis of Dutch origin, the present findings suggest that a brain mast cell chymotrypsin‐like protease may participate in generating perivascular β‐protein, which ultimately aggregates into β‐amyloid deposits.
Role of Intercellular and Intracellular Communication by Nitric Oxide in Coupling of Muscarinic Receptors to Activation of Guanylate Cyclase in Neuronal Cells
Authors: Hu Jingru , El‐Fakahany Esam E.
Published: July 2010

Abstract:Muscarinic receptor‐mediated cyclic GMP formation and release of nitric oxide (NO) (or a precursor thereof) were compared in mouse neuroblastoma N1E‐115 cells. [3H]Cyclic GMP was assayed in cells prelabeled with [3H]guanine. Release of NO upon the addition of muscarinic agonists to unlabeled neuroblastoma cells (NO donor cells) was quantitated indirectly by its ability to increase the [3H]cyclic GMP level in labeled cells whose muscarinic receptors were inactivated by irreversible alkylation (NO detector cells). Carbachol increased NO release in a concentration‐dependent manner, with half‐maximal stimulation at 173 μM(compared to 96 μMfor direct activation of cyclic GMP formation). The maximal effect of carbachol in stimulating release of NO when measured indirectly was lower than that in elevating [3H]cyclic GMP directly in donor cells. Hemoglobin was more effective in blocking the actions of released NO than in attenuating direct stimulation of [3H]cyclic GMP synthesis. There was a good correlation between the ability of a series of muscarinic agonists to release NO or to activate [3H]cyclic GMP formation directly, and the potency of pirenzepine in inhibiting the two responses. Furthermore, there was a similar magnitude of desensitization of both responses by prolonged receptor activation or stimulation of protein kinase C. NO release was also regulated in relation to the cellular growth phase. A model is proposed in which a fraction of NO generated upon receptor activation does not diffuse extracellularly and stimulates cyclic GMP synthesis within the same cell where it is formed (locally acting NO). The remainder of NO that is extruded extracellularly might travel to neighboring cells (neurotransmitter NO) or might be taken back into the cells of origin (homing NO).
Multiple Subtypes of Excitatory Amino Acid Receptors Coupled to the Hydrolysis of Phosphoinositides in Rat Brain
Authors: Littman Louis , Glatt Brian S. , Robinson Michael B.
Published: July 2010

Abstract:The excitatory amino acid (EAA) analogues quisqualate, ibotenate, and trans‐(±)‐1‐amino‐1, 3‐cyclopentanedicarboxylate (trans‐ACPD) activate the metabotropic EAA receptors that are coupled to the hydrolysis of Phosphoinositides (PI). Previous studies of hippocampal cross sections demonstrated that PI hydrolysis stimulated by these agonists can be inhibited by either L‐aspartate‐β‐ hydroxamate (L‐AβHA) or DL‐2‐amino‐3‐phosphonopropionate (DL‐AP3). The goal of the present studies was to determine if all metabotropic EAA receptors are sensitive to L‐AβHA and DL‐AP3. Two approaches were used. In the first, using cerebellar cross sections, the effects of these agonists and inhibitors were examined. The EC50values (the concentrations required to evoke half‐maximal stimulation) of quisqualate, ibotenate, andtrans‐ACPD in cerebellum were similar to the EC50values that we observed previously in hippocampus, but neither L‐AβHA nor DL‐ AP3 blocked PI hydrolysis. The EC50values were 0.65 ± 0.17 μMfor quisqualate, 12.8 ± 2.5 μMfor ibotenate, and 18.1 ± 3.1 μMfor trans‐ACPD. All data were best fit to theoretical curves that had Hill slopes of 1. In the second approach, another EAA analogue, D‐aspartate, was identified as an agonist that stimulates PI hydrolysis. The EC50for PI hydrolysis stimulated by D‐aspartate was 470 ± 90 μMin hippocampus. Neither L‐AβSHA nor DL‐AP3 blocked PI hydrolysis stimulated by D‐aspartate in hippocampus. Furthermore, antagonists of ionotropic EAA receptors, antagonists of other receptor systems coupled to PI hydrolysis, and inhibitors of the Na+‐dependent L‐glutamate transport process also did not block PI hydrolysis stimulated by D‐aspartate. These data support the presence of three pharmacologically distinct metabotropic EAA receptor subtypes.
2‐Deoxyglucose Enhances 1‐Methyl‐4‐Phenyl‐1, 2, 3, 6‐Tetrahydropyridine‐Induced ATP Loss in the Mouse Brain
Authors: Chan Piu , Langston J. William , Irwin Ian , DeLanney Louis E. , Di Monte Donate A.
Published: July 2010

Abstract:The effects of 2‐deoxyglucose (2‐DG), an inhibitor of the uptake and use of glucose, on ATP loss caused by the neurotoxicant 1‐methyl‐4‐phenyl‐1, 2, 3, 6‐tetrahydropyridine (MPTP) were determined in the mouse brain. 2‐DG alone had no effect on brain ATP levels, but when administered 30 min before MPTP exposure, 2‐DG significantly enhanced MPTP‐induced ATP reduction. This was reflected as an increase in ATP loss in the striatum (from 15 to 27%) as well as a significant decrease in ATP in the cerebellar cortex, an area of the brain that was not affected after exposure to MPTP alone. In mice pretreated with 2‐DG, striatal ATP levels remained significantly decreased for >8 h after MPTP administration. In contrast, ATP levels in the cerebellar cortex returned to normal values within 4 h from MPTP exposure. Mazindol, a catecholamine uptake blocker, completely protected against MPTP‐induced loss of striatal ATP in the absence of 2‐DG, but it only partially prevented striatal ATP decrease after administration of both 2‐DG and MPTP; mazindol was also ineffective in protecting against ATP loss caused by 2‐DG and MPTP in the cerebellar cortex. 2‐DG/MPTP‐induced ATP loss appeared to be associated with the presence of the 1 ‐methyl‐4‐phenylpyridinium (MPP+) metabolite because (1) the pattern of ATP recovery in the striatum and cerebellar cortex appeared to reflect the pattern of MPP+clearance from these areas of the brain (i.e., significant MPP+levels persisted longer in the striatum than in the cerebellar cortex), and (2) ATP decrease was completely prevented by blocking the conversion of MPTP to MPP+with the monoamine oxidase B inhibitor deprenyl. Data indicate that impairment of glucose metabolism dramatically enhances the effects of MPTP/MPP+on cerebral energy supplies, making these effects relatively nonselective for dopaminergic neurons of the nigrostriatal pathway.
Cellular Quantification of Tyrosine Hydroxylase in the Rat Brain by Immunoautoradiography
Authors: Blanchard Veronique , Raisman‐Vozari Rita , Savasta Marc , Hirsch Etienne , Javoy‐Agid France , Feuerstein Claude , Agid Yves
Published: July 2010

Abstract:We developed a rapid and sensitive radioimmunohistochemical method for the quantification of tyrosine hydroxylase (TH) at both the anatomical and cellular level. Coronal tissue sections from fresh‐frozen rat brains were incubated in the presence of a TH monoclonal antibody. The reaction was revealed with a35S‐labeled secondary antibody. TH content was quantified in catecholaminergic brain areas by measuring optical density on autoradiographic films or silver grain density on autoradiographic emulsion‐coated sections. Regional TH concentrations determined in the locus ceruleus (LC), substantia nigra pars compacta (SNC), and ventral tegmental area (VTA) were significantly increased by 45% after reserpine treatment in the LC but unchanged in the SNC and VTA. Microscopic examination of TH radioimmunolabeling showed a heavy accumulation of silver grains over catecholaminergic cell bodies. In the LC, grain density per cell was heterogeneous and higher in the ventral than in the dorsal part of the structure. After reserpine treatment, TH levels were significantly increased (57%) in the neurons of the LC but not in those of the SNC or VTA. The data support the validity of this radioimmunohistochemical method as a tool for quantifying TH protein at the cellular level and they confirm that TH protein content is differentially regulated in noradrenergic and dopaminergic neurons in response to reserpine.
Evoked Extracellular Dopamine In Vivo in the Medial Prefrontal Cortex
Authors: Garris Paul A. , Collins Leonard B. , Jones Sara R. , Wightman R. Mark
Published: July 2010

Abstract:The measurement of evoked extracellular dopamine in the medial prefrontal cortex by using fast‐scan cyclic voltammetry with carbon‐fiber microelectrodes was established and release characteristics of mesoprefrontal dopamine neurons were examined in vivo in anesthetized rats. Despite the sparse dopaminergic innervation and the presence of more dense noradrenergic and serotonergic innervations overall in the medial prefrontal cortex, the measurement of extracellular dopamine was achieved by selective recording in dopamine‐rich terminal fields and selective activation of ascending dopamine neurons. This was confirmed by electrochemical, pharmacological, and anatomical evidence. An increased release capacity for mesoprefrontal dopamine neurons was also demonstrated by the slower decay of the evoked dopamine response after inhibition of catecholamine synthesis and the maintenance of the evoked dopamine response at higher levels in the medial prefrontal cortex compared with the striatum during supraphysiological stimulation.
Inactivation and Subcellular Redistribution of Ca2+/ Calmodulin‐Dependent Protein Kinase II Following Spinal Cord Ischemia
Authors: Shackelford Deborah A. , Yeh Richard Y. , Zivin Justin A.
Published: July 2010

Abstract: Reversible spinal cord ischemia in rabbits induced a rapid loss of Ca2+/calmodulin‐dependent protein kinase II (CaM kinase II) activity measured as incorporation of phosphate into exogenous substrates. About 70% of the activity was lost from the cytosolic fraction of spinal cord homogenates after 15 min of ischemia preceding irreversible paraplegia, which takes 25 min in this model. The loss of enzyme activity correlated with a loss of in situ renaturable autophosphorylation activity and a loss of CaM kinase II α and β subunits in the cytosol detected by immunoblotting. CaM kinase II activity in the particulate fraction also decreased but the protein levels of the a and β subunits increased. Thus ischemia resulted in an inactivation of CaM kinase II and a sequential or concurrent subcellular redistribution of the enzyme. However, denaturation and renaturation in situ of the CaM kinase subunits immobilized on membranes partly reversed the apparent inactivation of the enzyme in the particulate fraction. CaM kinase II activity was restored after reperfusion following short (≤25 min) durations of ischemia but not after longer durations (60 min) that result in irreversible paraplegia. The ischemia‐induced inactivation of CaM kinase II, which phosphorylates proteins regulating many cellular processes, may be important in the cascade of events leading to delayed neuronal cell death.
Identification of Cortexin: A Novel, Neuron‐Specific, 82‐Residue Membrane Protein Enriched in Rodent Cerebral Cortex
Authors: Coulter Phillip M. , Bautista Erwin A. , Margulies Jody E. , Watson Joseph B.
Published: July 2010

Abstract: Nucleotide sequence analysis of a cDNA clone of a rat cortex‐enriched mRNA identifies a novel integral membrane protein of 82 amino acids. The encoded protein is named cortexin to reflect its enriched expression in cortex. The amino acid sequence of rat cortexin and its mouse homologue are nearly identical (98% similarity), and both contain a conserved single membrane‐spanning region in the middle of each sequence. Northern blot analysis shows that cortexin mRNA is brain‐specific, cortexenriched, and present at significant levels in fetal brain, with peak expression in postnatal rodent brain. In situ hybridization studies detect cortexin mRNA primarily in neurons of rodent cerebral cortex, but not in cells of the hindbrain or white matter regions. The function of cortexin may be particularly important to neurons of both the developing and adult cerebral cortex.
D2Receptors May Modulate the Function of the Striatal Transporter for Dopamine: Kinetic Evidence from Studies In Vitro and In Vivo
Authors: Meiergerd Susan M. , Patterson Terrell Ann , Schenk James O.
Published: July 2010

Abstract:Recently it was hypothesized by others that the D2dopamine receptor can regulate the uptake of dopamine. However, the evidence in support of this hypothesis, although compelling, was not based on observations related to direct measures of the kinetic activity of the transporter itself. Here kinetic evidence in support of this hypothesis is shown. The apparent time‐resolved initial velocity of the transport of 1.0 μMdopamine into striatal suspensions, measured using rotating disk electrode voltammetry, was found to increase in the presence of the D2receptor agonist, quinpirole, at 100 μM. This effect was reversed by sulpiride. In separate studies it was shown that acute and chronic treatments with haloperidol at 0.5 mg/kg, i.p., reduced the reuptake transport of dopamine in vivo following intrastriatal stimulation of its release by K+. Thus, it appears that D2receptors may influence the functioning of the striatal transporter for dopamine. These results are consistent with a model in which presynaptically released dopamine may feed back onto the function of its transporter to increase the velocity of the clearance of synaptic dopamine following an action potential, suggesting the existence of a mechanism, in addition to release and synthesis modulation, for fine‐tuning dopaminergic chemical signaling.
Dopamine D2Receptor‐Mediated Regulation of Serotonin Extracellular Concentration in the Dorsal Raphe Nucleus of Freely Moving Rats
Authors: Ferré Sergi , Artigas Francesc
Published: July 2010

Abstract:Morphological and pharmacological data suggest the existence of a reciprocal interaction between the mesencephalic dopamine (DA) system and the serotonin (5‐HT) system originating in the dorsal raphe nucleus (DRN). In the present work, a DA D2receptor‐mediated regulation of 5‐HT extracellular concentrations in the DRN is described, by using brain microdialysis in freely moving rats. Local infusion of the nonselective DA agonist apomorphine produced a dose‐dependent increase in the extracellular concentration of 5‐HT in the DRN, which was prevented by previous infusion of the specific D2antagonist raclopride but not of the D, antagonist SCH‐23390. Furthermore, local infusion of the selective D2agonist LY‐171, 555 increased extracellular 5‐HT levels in the DRN, and this effect was also prevented by the previous infusion of raclopride. It is postulated that DA, either from projections from the substantia nigra or the ventral tegmental area or from the DA‐containing neurons of the DRN, may increase 5‐HT release in the DRN, which, through autoreceptor stimulation, can profoundly influence the activity of ascending serotoninergic neurons.
Reduction of calcium release from the endoplasmic reticulum could only provide partial neuroprotection against beta‐amyloid peptide toxicity
Authors: Suen Ka‐Chun , Lin Kim‐Fung , Elyaman Wassim , So Kwok‐Fai , Chuen‐Chung Chang Raymond , Hugon Jacques
Published: July 2010

Beta‐amyloid (Aβ) peptide has been suggested to play important roles in the pathogenesis of Alzheimer's disease (AD). Aβ peptide neurotoxicity was shown to induce disturbance of cellular calcium homeostasis. However, whether modulation of calcium release from the endoplasmic reticulum (ER) can protect neurons from Aβ toxicity is not clearly defined. In the present study, Aβ peptide‐triggered ER calcium release in primary cortical neurons in culture is modulated by Xestospongin C, 2‐aminoethoxydiphenyl borate or FK506. Our results showed that reduction of ER calcium release can partially attenuate Aβ peptide neurotoxicity evaluated by LDH release, caspase‐3 activity and quantification of apoptotic cells. While stress signals associated with perturbations of ER functions such as up‐regulation of GRP78 was significantly attenuated, other signaling machinery such as activation of caspase‐7 transmitting death signals from ER to other organelles could not be altered. We further provide evidence that molecular signaling in mitochondria play also a significant role in determining neuronal apoptosis because Aβ peptide‐triggered activation of caspase‐9 was not significantly reduced by attenuating ER calcium release. Our results suggest that neuroprotective strategies aiming at reducing Aβ toxicity should include molecular targets linked to ER perturbations associated with ER calcium release as well as mitochondrial stress.
Cyclin‐dependent kinase‐5 in neurodegeneration
Authors: Shelton Shirley B. , Johnson Gail V. W.
Published: July 2010

Cyclin‐dependent kinase‐5 (CDK5) is predominantly active in the nervous system and it is well established that CDK5 is essential in neuronal development. In addition to its recognized role in development, there is increasing evidence that CDK5 may be involved in the pathogenesis of several neurodegenerative disorders. Although studies have shown that CDK5 can modulate cell death and survival, controversy still exists as to the exact role CDK5 may play in neurodegenerative processes. This review will highlight recent data on the possible roles of CDK5 in neurodegeneration.
Applications of nucleic acid technology in the CNS
Authors: Trülzsch Barbara , Wood Matthew
Published: July 2010

This review examines applications of nucleic acid technology in the form of catalytic nucleic acids (ribozymes and DNAzymes) and RNA interference (RNAi) in the CNS. The basic mechanism of catalytic nucleic acids and RNAi is reviewed, and potentials and problems highlighted. Recent advances in chemical modifications and delivery techniques are summarized. Applications in the CNS, including their use in primary neuronal cells, organotypic slice culture and the brainin vivoare further discussed.
Primed phosphorylation of tau at Thr231 by glycogen synthase kinase 3β (GSK3β) plays a critical role in regulating tau's ability to bind and stabilize microtubules
Authors: Cho Jae‐Hyeon , Johnson Gail V. W.
Published: July 2010

Site‐specific phosphorylation of tau negatively regulates its ability to bind and stabilize microtubule structure. Although tau is a substrate of glycogen synthase kinase 3β (GSK3β), the exact sites on tau that are phosphorylated by this kinasein situhave not yet been established, and the effect of these phosphorylation events on tau–microtubule interactions have not been fully elucidated. GSK3β phosphorylates both primed and unprimed sites on tau, but only primed phosphorylation events significantly decrease the ability of tau to bind microtubules. The focus of the present study is on determining the importance of the GSK3β‐mediated phosphorylation of a specific primed site, Thr231, in regulating tau's function. Pre‐phosphorylation of Ser235 primes tau for phosphorylation by GSK3β at Thr231. Phosphorylation by GSK3β of wild‐type tau or tau with Ser235 mutated to Ala decreases tau–microtubule interactions. However, when Thr231 alone or Thr231 and Ser235 in tau were mutated to Ala, phosphorylation by GSK3β did not decrease the association of tau with the cytoskeleton. Further, T231A tau was still able to efficiently bind microtubules after phosphorylation by GSK3β. Expression of each tau construct alone increased tubulin acetylation, a marker of microtubule stability. However, when cells were cotransfected with wild‐type tau and GSK3β, the level of tubulin acetylation was decreased to vector‐transfected levels. In contrast, coexpression of GSK3β with mutated tau (T231A/S235A) did not significantly decrease the levels of acetylated tubulin. These results strongly indicate that phosphorylation of Thr231 in tau by GSK3β plays a critical role in regulating tau's ability to bind and stabilize microtubules.
Potassium, sodium, calcium and glutamate‐gated channels: pore architecture and ligand action
Authors: Zhorov Boris S. , Tikhonov Denis B.
Published: July 2010

In the last decade, the idea of common organization of certain ion channel families exhibiting diverse physiological and pharmacological properties has received strong experimental support. Transmembrane topologies and patterns of the pore‐facing residues are conserved in P‐loop channels that include high‐selective cation channels and certain ligand‐gated channels. X‐ray structures of bacterial K+channels, KcsA, MthK and KvAP, help to understand structure‐function relationships of other P‐loop channels. Data on binding sites and mechanisms of action of ligands of K+, Na+, Ca2+and glutamate gated ion channels are considered in view of their possible structural similarity to the bacterial K+channels. Emphasized are structural determinants of ligand–receptor interactions within the channels and mechanisms of state‐dependent action of the ligands.
Impacts of Animal Well‐Being and Welfare Media on Meat Demand
Authors: Tonsor Glynn T. , Olynk Nicole J.
Published: July 2010

This article provides the first known examination of how animal welfare information provided by media sources impacts beef, pork and poultry demand. Results suggest that media attention to animal welfare has a small, but statistically significant impact on meat demand. Long‐run pork and poultry demand are hampered by increasing media attention whereas beef demand is not directly impacted. Loss in consumer demand is found to come from exiting the meat complex rather than spilling over and enhancing demand of competing meats. An outline of economic implications is provided for the broader discussion of animal welfare.
Some Aspects of the Drying and Heating of Textiles Part III–The Migration of Solvents and Solutes during Drying
Authors: PRESTON J. M. , CHEN J. C.
Published: July 2010

The migration of moisture and dissolved substanoes during drying operations has been investigated. Similar migration is found to ooour during the production of “fused” semi–stiff collars where liquids other than water are used.

A simple mechanism is proposed to explain the migration phenomena.
A Note on the Anisotrophy of Cellulose Acetate Fibres
Authors: PRESTON J.M. , ACKSON J.H.E.J , NIMKAR M.V.
Published: July 2010

An examination has been made of the anistropies of aome cellulose scetate fibers and of cellulose fibers regenerated from them. On comparison the celloulose fibers show comparable but somewhat larger anisotropies than the corresponding cellouls acetate fibers.
The Action of Light on Jute
Authors: CALLOW H. J. , SPEAKMAN J. B.
Published: July 2010

When jute is exposed to light and air, all the main components undergo degradation. An aqueous extract of the exposed material contains reducing substances, which may be aldehydes of low molecular weight derived from the cellulose by main chain fission, because the copper number of jute is increased by exposure. In addition, the aqueous extract is more acid than that from unexposed jute. Part of the acid seems to come from degraded polyuronides, and the remainder from the lignin, which loses methoxyl groups during irradiation. Their loss may lead to the formation of o–diphenols and, ultimately, o–quinones. These seem to be the main cause of the discolouration. which jute suffers during exposure to light and air.

in the light of these observations, it seemed probable that discolouration would be prevented by methylation or acetylation. Jute is bleached by treatment with diazomethane, but subsequent discolouration during exposure, though minimiaod, is not entirely prevented. Botter results were obtained hy first bleaching jute with sodium hypochlorite and hydrogen peroxide, and then acetylating with a mixture of acetic anhydride, xylene, and sulphanilic acid at the boil. Acetylation for 3 tir. gives a product which bleaches during irradiation, but some discolouration takes place during acetylation. When, however. the jute is treated for only 1 hr., the primary discolouration is minimised, and tho degree of acetylation is such that neither discolouration nor bleaching takes place during exposure.

The bleaching of highly aeetylated jute during irradiation is favoured by the presence of oxygen and water. Acetyl groups are lost during exposure, and it seems probable that bleaching is caused by the formation of acetyl peroxide, which was shown to be capable of bleaching aeetylated jute.
The Formation of Polymers in Wool*
Authors: LIPSON M. , SPEAKMAN J. B.
Published: July 2010

When wool fibres are impregnated with a dilute solution of ferrous ammonium sulphate, dried, and then treated with a solution of methacrylic acid containing a trace of hydrogen peroxide, preferential internal polymerisation is brought about by the hydroxyl radicals formed inside the fibres when the hydrogen peroxide encounters the ferrous ions. The reaction proceeds best at low j>H values in absence of oxygen. Preferential internal polymerisation of water–insoluble monomers can also be brought about if they are emulsified with Lissolamine V, and no difficulty has been encountered in forming copolymers of methacrylic acid and methyl methaerylate, for example, within the fibres.

Such internal deposits of polymer can be used to modify the properties of wool in a number of ways. When the polymer is acid, two–tone effects can be obtained by dyeing treated and untreated wool in the same dyebath, the treated wool taking a lighter shade. Conversely, when the polymer is basic, the treated wool takes a darker shade. In addition, internal deposits of polymer are capable of increasing the wear–resistance and reducing the milling shrinkage of wool fabrics. Finally, if the monomer carries reactive side–chains, e. g. methacrylamide, internal polymerisation followed by cross–linking with formaldehyde causes a striking increase in the resistance of wool fibres to extension in water. It is not yet known whethor cross–linkages are formed between the polymer and the wool, but reactions of this type should be useful in strengthening intact fibre and repairing damaged fibres.
The Reaction of Wool with Organic Chloroamines I–Conditions for rendering Wool Non–felting
Authors: ALEXANDER P. , CARTER D. , EARLAND C.
Published: July 2010

It is shown that certain chloroamines will react with wool to render it unshrinkable, but only in the presence of high concentrations of hydrogen and ohloride ions. In the absence of high concentrations of these ions the chloroamines still react with the wool, which does not, however, become unshrinkable unless very high concentrations are employed.

From a practical point of view the use of chlorosulphamic acid is most promising in the presence of high concentrations of sodium chloride, as small quantities of available chlorine then render the wool completely unshrinkable with a minimum of damage.
The Rise and Development of the Wool Dyes A Brief Historical Survey
Authors: Baddiley J.
Published: July 2010

The modern wool dyes owe nothing to Nature. They arose from attempts to make the sparingly soluble basic dyes of the pioneer period of dye synthesis more suitable for application from aqueous solution. The sulphonic acid group provided the clue to the development of the acid wool dyes. Sulphonation also opened the road to the discovery of the rich field of azo dye intermediates, which have been the source and inspiration of an immense range of cheap and versatile acid dyes for wool, supplemented by the brighter triphenylmethane acid dyes on the one hand, and the faster (to light) acid anthraquinone dyes on the other. Fastness to wet treatment and light was achieved by the discovery of dyes suitable for metallic complex formation. Acid dyes of this type ended the dependence of the wool dyer on natural colouring matters. Modern trends aim to avoid the fibre damage associated with the chrome dyog, either by improvement of the latter or by a departure from the idea of complex formation. New structural features have been introduced which promote fastness to wet treatment in ordinary acid dyes.
The Production of Metal Screens
Authors: Waller G.
Published: July 2010

A new method of producing printing screens from metal is described. Although the method requires a higher degree of technical skill and additional capital outlay compared with normal methods, improved results are obtainable in the life and accuracy of registration of screens, and in addition it is possible to gain greater control over the quality of printing by variation of the screen mesh.
Disulphide Bond Reactivity in Wool‐ Formation of Thiol Radicals on Exposure to Light
Authors: Crawshaw G. H. , Speakman J. B.
Published: July 2010

On exposure to diffuse light, stringently de‐aerated solutions containing methacrylic acid and sulphuric acid undergo polymerisation in a few hours at 25°c, in presence of ethyl disulphide, cystine, or intact wool, but not in their absence. The disulphides (including wool) are ineffective in the dark, and it is concluded that polymerisation is initiated by the thiol radicals which are produced by homolytic fission of the disulphide bonds under the influence of light‐R.S.S.R ‐ 2 R.S.