bluuebunny/crossref_metadata_2025 huggingface dataset:
ELEVATION OF CYCLIC GMP LEVELS IN CENTRAL NERVOUS SYSTEM BY EXCITATORY AND INHIBITORY AMINO ACIDS1
Authors: Ferrendelli J. A. , Chang M. M. , Kinscherf D. A.
Published: October 2006

—Guanosine 3′,5’cyclic monophosphate (cyclic GMP) levels in incubated slices of mouse cerebellum are increased 10‐fold by glutamate and two‐to three‐fold by glycine or γ‐aminobutyric acid (GABA). Glutamate also produces a 10‐fold increase in adenosine 3′,5’cyclic monophosphate (cyclic AMP) in the same tissue. However, GABA decreases cyclic AMP levels 30‐40 per cent, and glycine produces only a transient 50 per cent accumulation of this cyclic nucleotide. Theophylline slightly augments the accumulation of cyclic GMP produced by all three amino acids but markedly attenuates the accumulation of cyclic AMP produced by glutamate. In the absence of Ca2+, none of the three amino acids has any effect on cyclic GMP levels, and glutamate produces only a 50 per cent rise in cyclic AMP levels. The decrease of cyclic AMP levels produced by GABA is not affected by theophylline or by the absence of Ca2+. These data suggest an involvement of both cyclic GMP and cyclic AMP in the neurochemical actions of glutamate, GABA and glycine.
MUCOPOLYSACCHARIDES SYNTHESIZED BY CULTURED GLIAL CELLS DERIVED FROM A PATIENT WITH SANFILIPPO A SYNDROME
Authors: Fluharty A. L. , Davis Marsha L. , Trammell J. L. , Stevens R. L. , Kihara H.
Published: October 2006

—Glial cells were cultured from brain tissue obtained at autopsy of a patient with Sanfilippo A syndrome. Mucopolysaccharides were labeled by culturing the cells in the presence of [35S]sulfate. After proteolysis, intracellular and media‐elaborated mucopolysaccharides were fractionated by Dowex 1 chromatography. One fraction, identified as heparan sulfate by chromatographic, electrophoretic, and enzyme susceptibility properties, accumulated in Sanfilippo glial cells in greater amounts than in controls. Heparan sulfate was also excreted into the culture media by both Sanfilippo and normal cultures, and it constituted a major fraction of the sulfated mucopolysaccharides synthesized by glial cells. Sanfilippo and normal fibroblasts were also included in these studies for comparative purposes. Sanfilippo fibroblasts accumulated significantly increased amounts of heparan sulfate as compared to normal fibroblasts. Heparan sulfate was excreted into the culture media by Sanfilippo and normal fibroblasts in equivalent amounts, but in contrast to glial cells, it was only a minor component of the sulfated mucopolysaccharides produced. Cultured glial cells should provide a useful system for investigating the role of heparan sulfate in glial cell function.
RESERPINE SENSITIVITY OF CATECHOLAMINE METABOLISM IN MURINE NEUROBLASTOMA CLONE N1E‐1151
Authors: Breakefield Xandra O.
Published: October 2006

—Neuroblastoma cells of clone NIE‐115, originally obtained from the murine tumor C1300, resemble normal noradrenergic neurons in that they have high levels of tyrosine 3‐monooxygenase (EC 1.14.16.2; l‐tyrosine, tetrahydropteridine: oxygen oxidoreductase (3‐hydroxylating)) and dopamine β‐monooxygenase (EC 1.14.17.1; 3,4‐dihydroxyphenylethylamine, ascorbate: oxygen oxidoreductase (β‐hydroxylating)) activities, dense core versicles (100–300 nm in dia), long neurites and excitable membranes. These studies show that reserpine, a blocker of vesicular uptake in noradrenergic neurons, inhibits the accumulation and storage of catecholamines, as well as the conversion of dopamine to NE in neuroblastoma cells. Differentiated monolayer cultures took up [3H]dopamine [10−4] at a rate of 37 pmol/min per mg protein. Reserpine [5 × 10−5m] did not affect the initial rate of uptake, but reduced the extent of uptake at saturation by 60%. Chromatographic examination of cell extracts showed that dopamine was converted to NE in control cultures, but not in reserpine treated cultures. Cells labelled with [3H]dopamine for 60 min and then exposed to release buffer without dopamine for an additional 60 min, retained approximately 40% of the label, 10% as dopamine and 30% as NE. Thirty‐five per cent of the radioactivity retained was found, after homogenization and high speed centrifugation, to be associated with a particulate, subcellular fraction. Reserpine, present during release incubations, also reduced the ability of cells to store catecholamines. These results show that N1E‐115 cells synthesize and store NE by reactions similar to those in normal noradrenergic neurons.
CONVERSION OF [1‐14C]PALMITIC ACID TO [1‐14C]HEXADECANOL BY DEVELOPING RAT BRAIN CELL‐FREE PREPARATIONS
Authors: Natarajan V. , Sastry P. S.
Published: October 2006

—The conversion of [l‐14C]palmitic acid to [1‐14C]hexadecanol has been demonstrated with a cell‐free system from developing rat brain. ATP, Coenzyme A and Mg2+ were required for the activity. Fatty aldehyde was found to be an intermediate in this reaction. The conversion of fatty acid to fatty alcohol was mainly localized in the microsomal fraction and the formation of hexadecanol showed absolute specificity towards NADPH while fatty aldehyde was formed even in the absence of exogenous reduced pyridine nucleotides. The brain microsomes showed maximal activity with stearic acid and the activities with palmitic and oleic acids were 65% and 38% respectively of that with stearic acid. This enzymic reduction increased with age and showed a maximum in the 15‐day old rat brain.
GANGLIOSIDES OF PERIPHERAL NERVE MYELIN
Authors: Fong J. W. , Ledeen R. W. , Kundu S. K. , Brostoff S. W.
Published: October 2006

—Gangliosides have been isolated from myelin obtained from three types of peripheral nerve: bovine spinal roots, bovine sciatic nerve and human sciatic nerve. Yields in most cases were 218–287 μg of lipid‐bound sialic acid per g myelin, less than half that previously obtained from CNS myelin. Myelin accounted for approx 60% of total ganglioside present in whole spinal root. The human sample contained only N‐acetylneuraminic acid but the two bovine preparations contained that as well as N‐glycolylneuraminic acid; N‐acetylglucosamine and N‐acetylgalactosamine were both present in all three preparations. Sphingosine was the major long‐chain base in each preparation while 4‐eicosasphingenine (d20:1) comprised about 14% in the two bovine samples and 3% in the human sample. The major fatty acids in all preparations were 16:0, 18:0, 22:0, 24:0 and 24:1. Sialosylgalactosyl ceramide (G7), a ganglioside characteristic of CNS myelin, was not detected in any of the PNS samples. The majority of gangliosides in bovine spinal root myelin were monosialo species, although the structures differed in some respects from those of CNS myelin. The molar concentration of lipid‐bound sialic acid in PNS myelin is roughly equivalent to that of the P1 basic protein.
EFFECTS OF NOREPINEPHRINE ON THE MORPHOLOGY AND SOME ENZYME ACTIVITIES OF PRIMARY MONOLAYER CULTURES FROM RAT BRAIN
Authors: Narumi S. , Kimelberg H. K. , Bourke R. S.
Published: October 2006

Abstract—

Addition of norepinephrine or isoproterenol to primary cultures started from the brains of 1‐3 day old rats caused up to 200‐fold increases in cAMP levels, which reached a maximum by 5‐10 min and then declined. This effect was studied in detail for norepinephrine. The rise in cAMP levels was followed by morphological changes, in which up to 65% of the cells exhibited an astrocyte‐like morphology, and 2‐3 fold increases in carbonic anhydrase and (Na+‐K+) ATPase activities. However, morphological transformation also occurred after much smaller increases in total cAMP levels. These effects on cell morphology and enzyme activities reached a maximum 1‐2 h after addition of norepinephrine and then declined. Carbonic anhydrase activity was found both in the particulate and post 100,000 g supernatant fractions from homogenates of these cultured cells, and in the latter case the activity was activated 3‐fold by addition of cAMP. The significance of these obscrvations on the cellular localization of, and functional role for similar increases in cAMP in brain tissue is discussed.
Decreased Transmethylation of Biogenic Amines After In Vivo Elevation of Brain S‐Adenosyl‐l‐Homocysteine
Authors: Schatz Robert A. , Wilens Timothy E. , Sellinger Otto Z.
Published: October 2006

Abstract: The ability of S‐adenosyl‐l‐homocysteine (AdoHcy) to inhibit biologic transmethylation reactions in vitro has led us to explore the possibility of pharmacologically manipulating AdoHcy levels in vivo and examining the consequences of these alterations on the transmethylation of some biogenic amines. Swiss‐Webster mice were injected intraperitoneally with different doses of adenosine (Ado) and d,l‐homocysteine thiolactone (Hcy) and were killed at various times thereafter. S‐Adenosyl‐l‐methionine (AdoMet) and AdoHcy concentrations were determined by using a modified isotope dilution‐ion exchange chromatography‐high pressure liquid chromatography technique sensitive to less than 10 pmol. Increasing doses of Ado + Hcy (50‐1000 mg/kg of each) produced a dose‐related increase in blood, liver, and brain AdoHcy levels. At a dose level of 200 mg/kg Ado + Hcy, AdoHcy levels were markedly elevated, with minimal concomitant perturbations of AdoMet. This elevation was maximal 40 min after giving Ado + Hcy, returning to control values within 6 h. Ado + Hcy treatment resulted in decreased activities of catechol‐O‐methyltransferase, histamine‐N‐methyltransferase, and AdoHcy hydrolase in vitro. The cerebral catabolism of intraventricularly administered [3H]histamine (HA) was decreased in a dose‐related manner by Ado + Hcy treatment as evidenced by higher amounts of nonutilized [3H]HA in brain, concurrent decreases in [3H]methylhistamine formation, and decreases in the transmethylation conversion index. Steady state levels of HA also showed dose‐related increases after Ado + Hcy treatment. It is concluded that injections of Ado + Hcy can markedly elevate AdoHcy levels in vivo, which can, in turn, decrease the rate of transmethylation reactions.
Competition by Estrogens for Catecholamine Receptor Binding In Vitro
Authors: Paden Charles M. , McEwen Bruce S. , Fishman Jack , Snyder Lenore , DeGroff Valerie
Published: October 2006

Abstract: We have examined the ability of various steroids to compete for high‐affinity binding of 3H‐labeled ligands to catecholamine receptors in membranes prepared from rat cerebral cortex, striatum, and anterior pituitary. Ligands employed were: [3H]WB4101, [3H]prazosin, [3H]yohimbine, and [3H]clonidine (alpha‐noradrenergic); [3H]dihydroalprenolol (beta‐noradrenergic); [3H]spiperone and [3H]ADTN (dopaminergic). Only the 17β estrogens were effective and only binding of [3H]spiperone and [3H]ADTN in striatum and [3H]WB4101 and [3H]prazosin in cerebral cortex was reduced. Thus putative dopaminergic and alpha1‐noradrenergic sites alone appear to recognize estrogens. A slight competitive effect on [3H]spiperone binding to anterior pituitary membranes was also observed. Among the 17β estrogens tested, the most effective in all cases was the catechol estrogen 2‐hydroxyestradiol (2‐OHE2). The ability of 2‐OHE2 (IC50= 20–30 μM) to inhibit ligand binding to alpha1 receptors was comparable to that of norepinephrine (IC50= 10–20 μM), whereas for dopamine receptors in striatum and pituitary 2‐OHE2 was an order of magnitude less effective than dopamine (IC30= 12 μM) in reducing binding of 3H ligands. Estradiol‐17β and 2‐hydroxyestrone were also able to inhibit binding, but the order of steroid potency was different for alpha1 and dopaminergic receptors. Progesterone, testosterone, and corticosterone were without effect in all cases. These results show that there is specificity of steroid interactions with catecholamine receptors in the brain, both in terms of steroid structure and receptor type. The possible relevance of these interactions to neuroendocrine function is discussed.
ATP‐Citrate Lyase and Other Enzymes of Acetyl‐CoA Metabolism in Fractions of Small and Large Synaptosomes from Rat Brain Hippocampus and Cerebellum
Authors: Szutowicz Andrzej , Harris Norman F. , Srere Paul A. , Crawford Isaac L.
Published: October 2006

Abstract: The activities of choline acetyltransferase and ATP‐citrate lyase were significantly correlated (r = 0.995) in fractions of small and large synaptosomes isolated from rat hippocampus and cerebellum. The activities of these two enzymes did not correlate with those of pyruvate dehydrogenase, carnitine acetyltransferase, citrate synthase, acetyl‐CoA synthetase, lactate dehydrogenase, or with the rate of high‐affinity glutamate uptake in the synaptosomal fractions. The results provide additional evidence linking ATP‐citrate lyase to the cholinergic system in the brain.
Irreversible Activation of the Opiate Receptor of Neuroblastoma × Glioma Hybrid Cells by an Alkylating Benzomorphan Derivative
Authors: Hallermayer Klaus , Harmening Christine , Merz Herbert , Hamprecht Bernd
Published: October 2006

Abstract: The benozomorphan derivative (‐) ‐ 2 ‐[2 ‐ (p ‐bromoacetamidophenyl)ethyl] ‐ 5,9α ‐ dimethyl ‐ 2’‐ hydroxy ‐ 6,7 ‐ benzomorphan (BAB), capable of reacting with nucleophilic groups, acts on neuroblastoma × glioma hybrid cells as a potent, irreversible opiate agonist. Its potency in inhibiting the increase in cellular cyclic AMP, evoked by prostaglandin E1, is comparable to that of Leu‐enkephalin. This also applies to its capacity to compete with [3H]d ‐ Ala2 ‐ Met ‐ enkephalinamide ([3H]DAEA) in binding on cell membrane preparations. The comparatively lower potency of (‐) ‐ 2 ‐ [2 ‐ (p ‐acetamidophenyl) ‐ ethyl]‐5,9α ‐ dimethyl‐2′‐hydroxy‐5,7 ‐ benzomorphan (AB), which differs from BAB in the substitution of the bromoacetamido group by an acetamido group, is of the same order of magnitude as that of morphine. The covalent interaction of BAB with the opiate receptors is deduced from the observations that (1) it is not possible to wash away this compound from the receptors, (2) the potency of BAB in inhibiting the specific binding of [3H]DAEA increases with prolonged preincubation time, and (3) AB behaves as a reversible agonist.
Density of Thy‐1 on Axonal Membrane of Different Rat Nerves
Authors: Beech J. N. , Morris R. J. , Raisman G.
Published: October 2006

Abstract: The density of the cell surface antigen, Thy‐1, has been measured on the axonal plasma membrane of the optic and hypoglossal nerves, and on the sympathetic (preganglionic) chain of the superior cervical ganglion in the rat. For each, the amount of Thy‐1 in a standard length of nerve was determined. The amount of axonal plasma membrane in a similar length was then measured by use of a computer graphics system which determined the total length of membrane in electron micrographs of cross sections of nerve. The axons of the two peripheral nerves were found to have a similar density (1100–1500 molecules/μm2) of Thy‐1 on their surface, and this was two‐ to threefold higher than the density on axons of optic nerve (500 molecules/μm2). These figures indicate that the density of Thy‐1 on the surface of these axons is somewhat lower than that found on the cells of the lymphoid system. Moreover, contrary to the impression gained from previous determinations of Thy‐1 levels, axons in the peripheral nervous system do not necessarily have a lower density of Thy‐1 on their surface than do those of the central nervous system.
Immunohistochemical Localization of 2′,3′‐Cyclic Nucleotide 3′‐Phosphodiesterase and Myelin Basic Protein in the Chick Retina
Authors: Kohsaka Shinichi , Nishimura Yozo , Takamatsu Ken , Shimai Kazuyo , Tsukada Yasuzo
Published: October 2006

Abstract: Antisera against bovine 2′,3′‐cyclic nucleotide 3′‐phosphodiesterase (CNPase) and against chick myelin basic protein (MBP) were raised in New Zealand white rabbits. The specificity of CNPase antiserum was examined by Ouchterlony double‐immunodiffusion test and immunoadsorption assay. With use of the specific antiserum, immunohistochemical localizations of CNPase and MBP were investigated in the chick retina. Light microscopic immunohistochemical studies have shown that MBP is localized in the optic nerve fiber layer and that CNPase is localized in the optic nerve fiber and photo‐receptor layers. Electron microscopic immunohistochemical examinations demonstrated that the myelin‐like neural sheaths in the optic nerve fiber layer were clearly stained by both antisera, whereas the membranes of the Müller cell were not stained. In the photoreceptor layer, membranes of the inner and outer segments of rod and cone photoreceptor cells were intensely stained by CNPase antiserum. However, these portions were not stained by MBP antiserum. Membranes of bipolar cells, amacrine cells, horizontal cells, and ganglion cells were not stained by either antiserum.
Chromatographic and Histochemical Identification of Dopamine Within an Identified Neuron in the Leech Nervous System
Authors: Lent Charles M. , Mueller Richard L. , Haycock Dean A.
Published: October 2006

Abstract: Each segmental ganglion of the leech nervous system has two pairs of lateral roots extending to the body wall and viscera. A cluster of about eight neuron cell bodies is located proximal to the first major branch of each anterior root and is termed the anterior root ganglion (ARG). Only one of these eight cells is vitally‐stained by Neutral Red dye and fluoresces an intense blue‐green following the glyoxylic acid histochemical condensation. The emission spectrum of this anterior root cell (AR) is stable under continuous UV illumination and is bimodal, with peaks at about 480 and 515 nm. This spectrum is indistinguishable from that of millimolar solutions of dopamine (DA) in gelatin droplets following glyoxylic acid histochemistry. We utilized high performance liquid chromatography and an amperometric detector to measure DA within the AR neurosomata at 1.01 pmol/cell. The AR cells in this study had an average diameter of 23 μm and therefore, the minimum intrasomatal concentration of DA is 160 mM, an unusually high level for any neu‐rotransmitter. We measured DA in anterior axons at 0.83 pmol, in segmental ganglia at 1.07 pmol, and in longitudinal connectives at 0.16 pmol. Control neurosomata (Retzius cells) and axonal tracts which lack blue‐green fluorescence (posterior and distal anterior roots), had no detectable DA (<0.06 pmol/sample). These data establish that the catecholamine DA is responsible for the fluorescence of the AR cell.
Perturbation of Rat Brain Serotonergic Systems Results in an Inverse Relation Between Substance P and Serotonin Concentrations Measured in Discrete Nuclei
Authors: Barden Nicholas , Daigle Michel , Picard Vallier , Di Paolo Thérèse
Published: October 2006

Abstract: Since substance P (SP) has been demonstrated to coexist with serotonin (5‐HT) in the same population of neurons in the descending raphe system, we have studied the possibility of interactions between these neu‐rotransmitters in other brain areas. Brain nuclei were punched from frozen 300–μm slices of rat brain and extracted with 0.1 M HCIO4 or 2 M acetic acid prior to assay, respectively, of 5‐HT content by HPLC with electrochemical detection or SP content by specific radioimmunoassay. Ten days after injection of rats with the 5‐HT neurotoxin P‐chloroamphetamine (PCA, 10 mg/kg, B.W., i.p.) or 3 days after 5‐HT synthesis blockade with p‐chlorophenylalanine (PCPA, 300 mg/kg, B.W., i.p.), the 5‐HT content of all brain nuclei studied was reduced by means of, respectively, 50% and 81%. In PCA‐treated animals, the SP content of the periaqueductal grey matter was significantly increased; PCPA treatment caused, in addition, large increases in the SP content of five other brain nuclei. Blockade of 5‐HT receptors by methysergide (15 mg/kg for 5 days) did not significantly change 5‐HT levels or turnover, but resulted in 50–200% increases in the SP content of 10 of the 28 brain nuclei studied. Significant decreases in the SP content of numerous areas were seen following treatments (pargyline 30 mg/kg, alone or in combination with 5‐hydroxytryptophan, 60 mg/kg) that simultaneously increased 5‐HT levels. These results illustrate the modulation of distinct SP‐containing systems of the rat brain by perturbation of central serotoninergic pathways and indicate a reciprocal relationship between the SP and 5‐HT concentrations of numerous brain nuclei, in particular n. striae terminalis, n. raphe dorsalis, n. accumbens, n. septi, substantia grisea centralis, and n. raphes medianus.
Neutral and Acid Sphingomyelinases of Rat Brain: Somatotopographical Distribution and Activity Following Experimental Manipulation of the Dopaminergic System In Vivo
Authors: Sperker Erich R. , Spence Matthew W.
Published: October 2006

The activities of neutral, magnesium‐stimulated, and acid Sphingomyelinases were measured in five regions of rat brain. Neutral enzyme activity was 2‐3‐fold higher in striatum than in parietal cortex and 13‐fold higher than in cerebral white matter. Acid sphingomyelinase activity was more evenly distributed throughout these regions. Striatal neutral sphingomyelinase activity was not affected by treatment of rats with reserpine or haloperidol and was reduced (16%) by 6‐hydroxydopamine. Striatal acid sphingomyelinase was unaffected by reserpine and 6‐hydroxydopamine, and was increased (17%) by haloperidol. We conclude that neutral, magnesium‐stimulated sphingomyelinase activity differs in various regions of rat brain and is particularly enriched in the corpus striatum. However, it appears to be a constitutive component of tissue rather than a readily modulated regulatory element of the catecholaminergic system.
Cyclic Nucleotide‐Dependent Protein Kinases and Some Major Substrates in the Rat Cerebellum After Neonatal X‐Irradiation
Authors: Dolphin Annette C. , Detre John A. , Schlichter Doris J. , Nairn Angus C. , Yeh Hermes H. , Woodward Donald J. , Greengard Paul
Published: October 2006

Abstract: The levels of cAMP‐dependent protein kinase (type I), of cGMP‐dependent protein kinase, of protein I and of a 23,000 MW substrate for the cGMP‐dependent protein kinase were measured in cerebella from normal rats and in the cerebella from rats in which a selective loss of interneurons in the cerebellar cortex had been produced by X‐irradiation. A decrease was observed in the concentrations of cAMP‐dependent protein kinase and of protein I, whereas an increase was observed in the concentrations of cGMP‐dependent protein kinase and of the 23,000 MW substrate. The data, taken together with the results of other studies, support the interpretation that cAMP‐dependent protein kinase and protein I are distributed throughout the cerebellum, but that cGMP‐dependent protein kinase and the 23,000 MW substrate are highly concentrated in Purkinje cells.
Tetrahydrobiopterin and Total Biopterin Content of Neuroblastoma (N1E‐115, N2A) and Pheochromocytoma (PC‐12) Clones and the Dependence of Catecholamine Synthesis on Tetrahydrobiopterin Concentration in PC‐12 Cells
Authors: Bräutigam Matthias , Dreesen Rainer , Herken Hans
Published: October 2006

Abstract: Tetrahydrobiopterin content was determined in several clonal cell lines by reversed‐phase HPCL and subsequent electrochemical detection. The same chromatography system was used to determine the total biopterin (tetrahydrobiopterin and 7,8‐dihydrobiopterin) by fluorescence detection. The catecholamine‐producing clones neuroblastoma N1E‐115 and pheochromocytoma PC‐12 contained 96 and 60 ng tetrahydrobiopterin/mg protein, respectively. The corresponding amount for the neuroblastoma clone N2A was 36 ng/mg protein. The tetrahydrobiopterin content in C‐6 glioma cells was below the limit of detection. The total biopterin is about 20% above the tetrahydrobiopterin content. Tetrahydrobiopterin and biopterin from the cells were identified by coelution with standard solutions and by potential‐current relationship or emission and excitation spectra, respectively. Addition of 2,4‐diamino‐6‐hydroxypyrimidine, an inhibitor of biopterin synthesis from GTP, to the culture medium of PC‐12 cells resulted in a dose‐dependent decrease of tetrahydrobiopterin and total biopterin content within 4 h, suggesting that the cells are capable of synthesising the biopterin which was found. A decrease in intracellular tetrahydrobiopterin levels by different concentrations of 2,4‐diamino‐6‐hydroxypyrimidine reduces the cellular production of dihydroxyphenylalanine after inhibition of aromatic L‐amino acid decarboxylase, indicating that the concentration of tetrahydrobiopterin might be a limiting factor for catecholamine synthesis in catecholamine‐producing cells.
S‐100 and Other Acidic Proteins Promote Ca2+‐Independent Phosphorylation of Protamine Catalyzed by a New Protein Kinase from Brain
Authors: Qi De‐Fang , Turner R. Scott , Kuo J. F.
Published: October 2006

Abstract: A new protein kinase modulated by S‐100 (tentatively referred to as protein kinase X) was partially purified from pig brain extracts. The activity of protein kinase X, which was independent of Ca2+, was demonstrated when protamine (free base), but not protamine sulfate and other proteins (including histone), was used as substrate. The enzyme activity, found to distribute in both soluble and particulate fractions and to occur at the highest level in brain compared with other tissues (heart, kidney, liver, skeletal muscle, spleen, and testis) of rats, was also modulated by other acidic proteins (calmodulin, troponin C, and stimulatory modulator) in a Ca2+‐independent manner. S‐100 and other acidic proteins appeared to function as “substrate modifiers” by interacting with protamine (a highly basic protein), but not with the enzyme, thus rendering protamine in the complex a superior phosphate acceptor. The two isoforms of S‐100 (i.e., a and b) were equally effective. Although the enzyme was not inhibited by many agents (trifluoperazine, melittin, cytotoxin I, polymyxin B, and spermine) shown to inhibit markedly phospholipid/Ca2+‐ or calmodulin/Ca2+‐stimulated protein kinase, gossypol was found to inhibit specifically protein kinase X. The present findings suggest that S‐100, a major acidic protein specific to nervous system, may promote phosphorylation by protein kinase X of certain neural proteins resembling protamine or containing protamine‐like domains, in addition to its presumed role of a low‐affinity Ca2+‐binding protein.
Modulation by Unsaturated Fatty Acids of Norepinephrine‐ and Adenosine‐Induced Formation of Cyclic AMP in Brain Slices
Authors: Baba Akemichi , Tatsuno Tohru , Iwata Heitaroh
Published: October 2006

Abstract: The effect of linoleic acid on the formation of cyclic AMP in the slices of guinea pig cerebral cortex was examined. Treatment of the slices with linoleic acid resulted in an increase of basal and of norepinephrine‐stimulated formation of cyclic AMP. The stimulatory effect on the basal level of cyclic AMP was not specific for linoleic acid: the potency of the fatty acid was related to the magnitude of unsaturation. In contrast, the enhancement of norepinephrine‐stimulated formation of cyclic AMP seemed relatively specific for linoleic acid and arachidonic acid. Linoleic acid markedly enhanced the stimulated formation of cyclic AMP by histamine and adenosine, as well that by norepinephrine, without affecting that by excitatory amino acids and veratridine. Theophylline, adenosine deaminase, and 2′‐deoxyadenosine antagonized the effect of linoleic acid. Linoleic acid enhanced the maximum responses to norepinephrine and adenosine without altering the ED50 values for these agonists. When linoleic acid‐treated slices were washed with Krebs‐Ringer containing defatted bovine serum albumin, both enhancement of the response to norepinephrine and the amount of [14C]linoleic acid incorporated in a free form significantly diminished.
(6R)‐Tetrahydrobiopterin Increases the Activity of Tryptophan Hydroxylase in Rat Raphe Slices
Authors: Sawada Makoto , Sugimoto Takashi , Matsuura Sadao , Nagatsu Toshiharu
Published: October 2006

Abstract The effects of (6R)‐ and (6S)‐tetrahydrobiopterin (BPH4), tetrahydroneopterin, and 6‐methyltetrahydropterin on the activity of tryptophan hydroxylase were investigated in rat raphe slices. The activity of tryptophan hydroxylase was estimated by measurement of 5‐hydroxytryptophan (5‐HTP) formation under inhibition of aromatic L‐amino acid decarboxylase with use of HPLC‐fluorometric detection. (6R)‐BPH4 (the naturally occurring form) at 42 μM, tetrahydroneopterin at 50 μM, and 6‐methyltetrahydropterin at 100 μM increased tryptophan hydroxylase activity to 350, 145, and 146% of control values, respectively. (6S)‐BPH4, however, had no significant effects on tryptophan hydroxylase activity. These results suggest that tryptophan hydroxylase is subsaturating in vivo for the naturally occurring cofactor, (6R)‐BPH4, and that the concentration of (6R)‐BPH4 may play an important role for the regulation of tryptophan hydroxylase activity in vivo.
Regulation of Hermissenda K+ Channels by Cytoplasmic and Membrane‐Associated C‐Kinase
Authors: Alkon D. L. , Naito S. , Kubota M. , Chen C. , Bank B. , Smallwood J. , Gallant P. , Rasmussen H.
Published: October 2006

Abstract: Pharmacologic activation of endogenous protein kinase C (PKC) together with elevation of the intracellular Ca2+ level was previously shown to cause reduction of two voltage‐dependent K+ currents (IA and Ica2+‐K+) across the soma membrane of the type B photoreceptor within the eye of the mollusc Hermissenda crassicornis. Similar effects were also found to persist for days after acquisition of a classically conditioned response. Also, the state of phosphorylation of a low‐molecular‐weight protein was changed only within the eyes of conditioned Hermissenda. To examine the role of PKC in causing K+ current changes as well as changes of phosphorylation during conditioning (and possibly other physiologic contexts), we studied here the effects of endogenous PKC activation and exogenous PKC injection on phosphorylation and K+ channel function. Several phosphoproteins (20, 25, 56, and 165 kilodaltons) showed differences in phosphorylation in response to PKC activators applied to intact nervous systems or to isolated eyes. Specific differences were observed for membrane and cytosolic fractions in response to both the phorbol ester 12‐deoxyphorbol 13‐isobutyrate 20‐acetate (DPBA) or exogenous PKC in the presence of Ca2+ and phosphatidylserine/diacylglycerol. Type B cells pretreated with DPBA responded to PKC injection with a persistent reduction of K+ currents. In the absence of DPBA, PKC injection also caused K+ current reduction only following Ca2+ loading conditions. However, the direct effect of PKC injection in the absence of DPBA was only to increase ICa2+_K+. According to a proposed model, the amplitude of the K+ currents would depend on the steady‐state balance of effects mediated by PKC within the cytoplasm and membrane‐associated PKC. The model further specifies that the effects on K+ currents of cytoplasmic PKC require an intervening proteolytic step. Such a model predicts that increasing the concentration of cytoplasmic protease, e.g., with trypsin, will increase K+ currents, whereas blocking endogenous protease, e.g., with leupeptin, will decrease K+ currents. These effects should be opposed by preexposure of the cells to DPBA. Furthermore, prior injection of leupeptin should block or reverse the effects of subsequent injection of PKC into the type B cell. All of these predictions were confirmed by results reported here. Taken together, the results of this and previous studies suggest that PKC regulation of membrane excitability critically depends on its cellular locus. The implications of such function for long‐term physiologic transformations are discussed.
Type I and Type II γ‐Aminobutyric Acid/Benzodiazepine Receptors: Purification and Analysis of Novel Receptor Complex from Neonatal Cortex
Authors: Sato Thomas N. , Neale Joseph H.
Published: October 2006

Abstract The γ‐aminobutyric acid (GABA) type A receptor was purified several thousandfold by affinity chromatography from rat cerebellum, adult cortex, and neonatal cortex. Competition for the benzodiazepine binding site by CL 218872 indicated that cerebellar receptors were predominantly type I, adult cortical receptors were a mixture of subtypes, and neonatal cortex was enriched in type II receptor. The receptor purified from neonatal cortex contained predominantly a 54‐kilodalton (kDa), β‐subunit‐like protein, whereas receptors from cerebellum and adult cortex contained nearly equal amounts of a 50‐kDa, α‐subunit‐like protein and a 54‐kDa polypeptide. Peptide maps of trypsin‐digested 54‐kDa subunits from cerebellum, adult cortex, and neonatal cortex exhibited very similar profiles, a result indicating considerable homology between these proteins in the receptor subtypes. A 59‐kDa subunit protein was detected in the receptor complex purified from neonatal cortex. Like the 50‐kDa, α‐subunit of the type I receptor, this protein was photolabeled with [3H] flunitrazepam. The photolabeled peptide fragments, produced by trypsin digestion of these α50‐ and α59‐subunits, exhibited the same retention times on reverse‐phase HPLC. A less highly purified GABAA receptor preparation from adult rat spinal cord possessed characteristics that were very similar to those of the receptors purified from neonatal cortex.
Expression of a Human Cocaine‐Sensitive Dopamine Transporter in Xenopus laevis Oocytes
Authors: Bannon Michael J. , Xue Chang‐Hong , Shibata Kazuhiko , Dragovic Ljubisa J. , Kapatos Gregory
Published: October 2006

The human dopamine transporter was expressed in Xenopus laevis oocytes following injection of mRNA isolated from human brain substantia nigra. The specific accumulation of [3H]dopamine into these oocytes was time and Na+ dependent. Furthermore, [3H]dopamine accumulation was prevented by coincubation of oocytes with dopamine (100 μM) or with the dopamine uptake inhibitors GBR 12909 (1 μM) or cocaine (3 μM). In contrast, oocyte injection of mRNA isolated from human globus pallidus, an area devoid of dopamine neuron perikarya, did not elicit expression of the dopamine transporter. Oocyte expression of the human dopamine transporter can be used for the further characterization and cloning of this low‐abundance membrane protein.
Inhibition of β Hemolytic Streptococci Fibrinolysin by Trypsin Inhibitor (Antiprotease)
Authors: Mirsky I. Arthur
Published: October 2006

Crystalline "trypsin-inhibitor" of pancreatic origin and the antitrypsin of soybean origin completely inhibit the fibrinolytic activity of cultures of β hemolytic streptococci, of filtrates of such cultures and of concentrates of such filtrates. It is suggested that the streptococcal fibrinolysin is a protease and that it may be related to trypsin.

The author wishes to acknowledge gratefully the cooperation of Lieutenant Colonel Robert L. King, Lieutenant Colonel E. D. Embree and Captain Edward Freis.
The Experimental Transmission of Pinta, Mal del Pinto or Carate to the Rabbit
Authors: León-Blanco Francisco , Oteiza Alberto
Published: October 2006

In this preliminary note we describe the results obtained by inoculation of the skin of the scrotum of four black rabbits with serous fluid expressed from an initial pinta lesion. The inoculation was made intradermally, as superficially as possible, with serous fluid rich in treponemata and diluted with normal salt solution. A papule appeared at the point of inoculation in one of the four rabbits on the 105th day. One hundred and fifteen days after inoculation the papule presented a circular erosion on an indurated base. The serous fluid expressed from this lesion contained numerous treponemata on dark-field examination, and these were easily impregnated by the Fontana-Tribondeau method. A volunteer inoculated with serous fluid expressed from the rabbit's lesion developed a typical initial pinta lesion at the point of inoculation, thus proving that the scrotal lesion of the rabbit was produced by
Treponema carateum
or
Treponema herrejoni
, the causal agent of pinta, mal del pinto or carate.

Four rabbits inoculated with serous fluid from the scrotal lesion of the rabbit have not yet developed visible lesions.
Comparative Toxicity of DDT Isomers and Related Compounds to Mosquito Larvae and Fish
Authors: Ginsburg Joseph M.
Published: October 2006

The p,p′-DDT isomer is several times as toxic as the o,p′-DDT isomer to both goldfish and mosquito larvae. The methoxy analogue equals DDT in toxicity to fish, but is less toxic to mosquito larvae. On the other hand, the DDD analogue ranks about as high as DDT in toxicity to mosquito larvae, but appears to be less toxic to goldfish.
Experimental Diabetes and Diet
Authors: Houssay B. A. , Martínez C.
Published: October 2006

In the experiments described the following observations have been made:

(1) The toxic and diabetogenic action of alloxan increases in rats fed a low protein diet and even more so in the case of a high lard or ox fat diet.

(2) The action of these fat diets was corrected by the addition of methionine, thiouracil, or coconut oil, but there was no modification either by addition of choline or sulfonamide or by increase in the protein proportion.

(3) In rats fed other high fat diets (olive oil, butter) the actions of alloxan were not modified, but there was a slight diminution when high oleomargarine or corn oil diets were fed. However, complete protection was observed when a high coconut oil diet was administered.

(4) The unfavorable effect of the high lard diet was observed also on the initiation and evolution of diabetes due to subtotal pancreatectomy. Contrarily, feeding a high protein diet and especially treatment with thiouracil had a favorable effect.

(5) Diabetes appeared first in subtotal pancreatectomized rats which were overfed, then in those which ate ad libitum, and finally in those which were underfed. Diabetes appeared in rats fed a single meal before it did in those eating the same amount of food divided into three meals.
Goals and Trends of Research in Geology and Geography
Authors: Rich John L.
Published: October 2006

Summarizing in a few words the essence of the preceding analysis of goals and trends in research in Geology and Geography, we may say that the goal in Geology is a knowledge and understanding of the earth and of its history. In Geography it is a knowledge and understanding of the natural and human environments, to the end that they may best be utilized toward better living in the broadest sense.

Trends in research in these sciences that seem not altogether desirable are those toward overorganization of research and overdirection from others than the ones who are to do the work; toward indiscriminate fact-gathering; toward lessening of critical analysis of, and discussion of, papers given at meetings and of the published results; and toward premature publication and excessive volume of publications resulting from the prevailing practice of soliciting papers for scientific meetings.

Changes in methods of financing of research resulting from a great decrease in endowment incomes are noted, together with a strong tendency to look toward the Federal Government for the financing of university research, in spite of the obvious dangers to university freedom which such financing involves.
Implication of
Phlebotomus
Sand Flies as Vectors of Bartonellosis and Leishmaniasis as Early as 1764
Authors: Herrer Aristides , Christensen Howard A.
Published: October 2006

A written account implicating
Phlebotomus
sand flies as vectors of Carrion's disease and cutaneous leishmaniasis in Peru was published by Cosme Bueno in 1764. Bueno's report precedes other publications implicating sand flies in the transmission of human pathogens by nearly a century and a half.
Stimulated Vasopressin Synthesis by a Fetal Hypothalamic Factor
Authors: Pearson David B. , Goodman Rosanne , Sachs Howard
Published: October 2006

The hypothalamo-neurohypophyseal complex (HNC) of the fetal guinea pig shows a dramatic increase in its content of vasopressin and neurophysin between the 40th and 55th days of gestation. The values for radioimmunoassayable hormone and binding protein are at day 40, 2 milliunits and less than 0.1 microgram; and at day 55, about 100 milliunits and 10 micrograms, respectively. Isotope incorporation experiments with organ cultures of the fetal HNC taken prior to the 35th day of gestation added additional confirmation of the inability of the hypothalamic neurosecretory cells to synthesize vasopressin or neurophysin at this time. However, by the 45th day, similar organ cultures show a vigorous incorporation of labeled amino acids into both hormone and binding protein. Furthermore, the HNC of the 45-day-old fetus apparently contains a factor that stimulates specifically the biosynthesis of vasopressin and neurophysin in HNC cultures from the adult guinea pig. This factor is not detectable in either cortex or liver of the 45-day-old fetus or in the fetal HNC taken prior to or after the period of exponential rise (40th to 55th days) of hormone and binding protein.
Partition of Gross Peripheral Nerve Activity into Single Unit Responses by Correlation Techniques
Authors: Heetderks W. J. , Williams W. J.
Published: October 2006

The neural activity in the medial articular nerve is partitioned on the basis of conduction velocity by correlation techniques. Because of the small number of cat knee joint units (two to ten) responding under a prescribed set of rotational conditions, it is possible to partition and simultaneously study the units' responses to periodic joint articulation waveforms.
Colonial Nervous Control of Lophophore Retraction in Cheilostome Bryozoa
Authors: Thorpe J. P. , Shelton G. A. B. , Laverack M. S.
Published: October 2006

Nervous impulses causing lophophore retraction over large areas of
Membranipora membranacea
and
Electra pilosa
were recorded with external electrodes. The response propagates at about 100 centimeters per second, presumably through the colonial nerve plexus of Hiller and Lutaud. Impulses are rapid up to 200 per second. A second impulse was recorded from individual zooids, probably generated by the polypide's nervous system. The retractor muscle shortens at more than 20 times its own length per second and is apparently the most rapidly contracting muscle known.
Inhibition of the Growth and Development of a Transplantable Murine Melanoma by Vitamin A
Authors: Felix Edward L. , Loyd Betty , Cohen Max H.
Published: October 2006

Vitamin A, given either orally or intraperitoneally, has a dramatic inhibitory effect on the growth and development of a highly immunogenic murine melanoma. This effect may be due to enhancement of antitumor immunity by vitamin A.
Distribution of Concanavalin A Receptor Sites on Specific Populations of Embryonic Cells
Authors: Roberson Marie , Neri Anthony , Oppenheimer Steven B.
Published: October 2006

The early 32- to 64-cell stage of the sea urchin embryo consists of three cell types, easily distinguishable by size: micromeres, mesomeres, and macromeres. Only the micromeres are migratory. Treatment of dissociated sea urchin embryo cells with fluorescein-labeled concanavalin A (Con A) revealed a Con A-induced highly clustered or capped distribution of receptor sites on the micromeres. Concanavalin A did not induce significant clustering or capping of receptor sites on the mesomeres or macromeres. The results indicate that Con A receptor sites are more mobile on specific populations of malignant-like migratory embryonic cells.
Prolongation of Gestation by Growth Hormone: A Confounding Factor in the Assessment of Its Prenatal Action
Authors: Croskerry P. G. , Smith G. K.
Published: October 2006

The administration of purified growth hormone to normally nourished pregnant rats prolonged gestation leading to postmaturity of the offspring. The effect explains, in part, the apparent influence of growth hormone on prenatal and early postnatal development and supports the notion that the prenatal action of exogenous growth hormone is restricted to a therapeutic one under conditions of malnutrition.
Occurrence of
S
-Methyl Thioesters in Urines of Humans After They Have Eaten Asparagus
Authors: White Robert H.
Published: October 2006

Gas chromatography-mass spectrometry was used to determine the odor-causing agent (or agents) present in the urines of humans after they have eaten asparagus.
S
-Methyl thioacrylate and
S
-methyl 3-(methylthio)thiopropionate were identified from methylene chloride extracts of such urines and appear to be the odor-causing compounds. Methanethiol, the previously reported odor-causing agent, was not detected in these methylene chloride extracts.
Goldfish Abducens Motoneurons: Physiological and Anatomical Specialization
Authors: Sterling Phyllis , Gestrin Peter
Published: October 2006

During natural movements, the motoneurons innervating a single muscle have different patterns of activity that are correlated with differences in synaptic input. The caudal abducens motoneurons fire phasically in synchronous bursts before rapid posterior eye movements; the rostral abducens motoneurons fire only tonically when the eye is fixed or moving slowly. This physiological difference is not related to motoneuron size. In this respect the abducens motoneurons violate the "size principle" that has been advanced for spinal motoneurons. The difference is probably related to the present finding that the caudal but not the rostral cells receive numerous electrical synapses that are known to have a role in synchronizing phasic activity.
Coping with Fraud
Authors: Broad William J.
Published: October 2006

The tardiness of actions by Harvard officials when faced with confessed fraudulent research conducted by John Darsee is contrasted with the more rapid responses by authorities in the cases of William T. Summerlin (Sloan-Kettering) and Vijay Soman (Yale).
Parathyroid Hormone and 25-Hydroxy Vitamin D
3
: Synergistic and Antagonistic Effects on Renal Phosphate Transport
Authors: Puschett Jules B. , Beck William S. , Jelonek Adam
Published: October 2006

The effect on phosphate excretion of graded doses of parathyroid hormone (PTH) and the biologically active vitamin D
3
metabolite, 25-hydroxycholecalciferol (25-HCC), administered singly and in combination, were studied in the nonexpanded, vitamin D-depleted thyroparathyroidectomized rat. Infusion of 1 unit of 25-HCC per hour for 6 hours induced an antiphosphaturia only when administered with 0.2 unit of PTH per hour, while neither agent alone changed phosphate excretion. A dose of 2.0 units of PTH per hour did not cause phosphaturia unless given with 1 unit of 25-HCC per hour. In pharmacologic dosage (5 units per hour), PTH produced phosphaturia in the absence of the metabolite.
Auditory Fatigue: Retrocochlear Components
Authors: Salvi R. , Henderson D. , Hamernick R.
Published: October 2006

Changes in auditory sensitivity were measured at the VIII nerve, cochlear nucleus, and inferior colliculus after a fatiguing sound exposure. Losses in sensitivity progressively increased from peripheral to central auditory sites. The results suggest that there is a retrocochlear component to auditory fatigue when it is induced by low-level sounds of short duration.
Delayed-Type Hypersensitivity to Sheep Red Blood Cells: Inhibition of Sensitization by Interferon
Authors: De Maeyer-Guignard Jaqueline , Cachard Annie , De Maeyer Edward
Published: October 2006

Interferon, when given or induced 24 hours before contact of mice with sheep red blood cells, prevented sensitization, and no delayed-type hypersensitivity reaction could be elicited 4 days later, after challenge with the antigen, as shown by the absence of footpad swelling in treated animals.
Guanidinium-CsCl Density Gradients for Isopycnic Analysis of Nucleic Acids
Authors: Enea Vincenzo , Zinder Norton D.
Published: October 2006

The addition of guanidinium chloride to CsCl gradients lowers the apparent density of RNA, DNA, and hybrid polymers in such a way that all three can be banded, fractionated, and analyzed in one gradient with essentially no damage to their chemical integrity or to their biological activity.