bluuebunny/crossref_metadata_2025 huggingface dataset:
Prolonged unit responses in thalamic reticular, ventral, and posterior nuclei following lateral hypothalamic and midbrain reticular stimulation
Authors: Keene James J.
Published: January 2005

In unanesthetized postcollicular cerveau isolé rats, prolonged responses over 10 sec periods following intracranial stimulation (0.2 sec, 100 Hz, 0.5 msec, 600 μA cathodal pulses) were studied with extracellular recordings of 150 nucleus reticularis and 122 ventral and posterior thalamic units. After medial forebrain bundle (MFB) or midbrain reticular (RET) stimulation, most nucleus reticularis units showed significantly decreased firing, and the MFB and RET effects converged on 64%. None was excited. In ventral and posterior thalamus, however, long‐lasting unit responses were mixed. MFB and RET stimuli elicited significantly increased firing in 17% and 20% of the units, respectively, and decreased firing in 21% and 16%, respectively. Convergence of MFB‐ and RET‐elicited responses occurred in 25% of the cells, but none showed convergence of opposite responses which might reflect believed motivational differences between the stimuli. Similar stimuli delivered to ventral medial thalamus evoked pronounced excitation of nucleus reticularis discharge, contrasting the MFB and RET effects and confirming previous reports by others. The substantial responses elicited by MFB and RET stimuli in nucleus reticularis fulfill previously proposed criteria for definition of an arousal dimension in terms of single cell activity. The similarity of MFB and RET effects in the posterior nucleus of thalamus raises questions regarding its role in nociception.
3‐methoxy‐4‐hydroxy‐phenylglycol sulfate (MOPEG‐SO4) in ventricular and cisternal cerebrospinal fluid of dogs
Authors: Bareggi Silvio R. , Stabenau James R. , Shaskan Edward G. , Becker Robert E. , Roberts Melville
Published: January 2005

Cerebrospinal fluid was collected from the lateral ventricles and cisternal space from beagle dogs under light pentobarbital anesthesia. Homovanillic acid (HVA), 5‐hydroxyindoleacetic acid (5‐HIAA), and 3‐methoxy‐4‐hydroxyphenylglyco‐sulfate (MOPEG‐SO4) level in the liquor taken from these two regions were evaluated, and the ventricular‐cisternal ratio (V/C) was calculated for each monoamine metabolite. A marked similarity in the V/C ratio of 6:1 for 5‐HIAA and 5:1 for MOPEG‐SO4, as compared to a much higher V/C ratio of 18:1 for HVA, perhaps reflects the more diffuse distribution of norepinephrine and serotonin, precursor amines, as compared to dopamine in the CNS and also emphasizes the probable existence of an active transport mechanism for the removal of MOPEG‐SO4, as has been well documented for 5–HIAA and HVA.
Biosynthesis of DNA and RNA in neuronal and glial cells from various regions of developing rat brain
Authors: Giuffrida A. M. , Hamberger A. , Serra I.
Published: January 2005

Slices of cerebral hemispheres, brain stem, and cerebellum from rats 5–30 days old were used for in vitro incorporation of [methyl‐3 H] thymidine and [6‐14 C] orotic acid into DNA and RNA, respectively. The rates of DNA and RNA synthesis decreased markedly during development, with the most marked decrease observed for DNA. The different brain regions showed specific patterns of decline of DNA and RNA synthesis. Following incubation of slices, the tissues were fractionated to obtain fractions enriched in neuronal cells and in glial cells. In cerebellum, the granule neurons were separated from the Purkinje neurons. The glial: neuronal ratio of DNA specific activity was different in the three regions examined: in cortex it decreased from 6 at 10 days to 3 at 20–30 days; in brain stem it was 3 throughout 10–30 days; in the cerebellum (glia:granule neuron ratio) it was also 3 at 30 days but only 0.3 at 10 days. Concerning the RNA incorporation, small differences were found between neuronal and glial cells.
Effects of hippocampal and amygdalar stimulation on uptake and binding of 3H‐hydrocortisone in the hypothalamus of the cat
Authors: Stith Rex D. , Person Robert J. , Dana Richard C.
Published: January 2005

Stimulation of the hippocampus or amygdala of adrenalectomized cats occurred for 10 sec followed by a 50 sec period of no stimulation, beginning 30 min prior to and ending 30 min after administration of 100 μCi of 3H‐hydrocortisone into a lateral ventricle. Sixty min after administration of labeled hormone, the hypothalamus was excised and homogenized. Cytosol and nuclear extract fractions were obtained and analyzed for radioactivity and protein content. Separation of bound from free hydrocortisone was achieved by charcoal adsorption assay.

Results reveal that stimulation of the hippocampus resulted in a greater concentration of 3H‐hydrocortisone taken up into hypothalamic cells. Also, a greater percentage of total hormone found in the nuclear extract was assayed as bound 3H‐hydrocortisone, and the concentration of bound radioactivity in the nuclear extract was increased over control values. Amygdalar stimulation, in general, yielded results similar to those obtained from control cats. However, although a lesser percentage of total hormone in the hypothalamic cytosol was assayed as bound hormone, there was a greater concentration of nuclear bound hormone than in controls, but less than that determined in the hippocampal stimulation group.

These results add to the evidence that hippocampus and amygdala have a modulating influence upon the hypothalamo‐hypophyseal axis. They also suggest that one manner in which these limbic structures may influence hypothalamic function is to modulate the uptake and binding of hydrocortisone in hypothalamic cells.
Biochemical studies of taste sensation: II. Labeling of cyclic amp of bovine taste papillae in response to Sweet and bitter stimuli
Authors: Cagan Robert H.
Published: January 2005

Labeling of cyclic AMP of taste papillae and its responsiveness to taste stimuli has been measured using whole papillae from bovine tongue prelabeled with [8‐14 C] adenine. Labeling was measured in circumvallate and fungiform papillae, both of which contain taste buds, and in filiform papillae and small blocks of tongue epithelium, which are devoid of taste buds. No differences were observed in the levels of activity.

The labeling of cyclic AMP of circumvallate papillae showed only small increases (12–22%) in the presence of the taste stimulus sucrose (sweet), and the stimulatory effects were not statistically significant. The increase due to sucrose was not potentiated by theophylline. No stimulation by sucrose was observed with epithelium controls. Lactose, which is a poor taste stimulus, did not stimulate labeling of cyclic AMP in taste papillae. Theophylline, caffeine, and quinine (bitter) stimulated labeling of cyclic AMP by up to 2‐fold, as did L‐Epinephrine.

Evidence for a specific role of cyclic AMP as a second messenger in taste sensation was not obtained. It is suggested that cyclic AMP might provide a mechanistic basis for studying some of the effects of sweet and bitter compounds in mixtures.
Effects of anesthesia level and stimulus characteristics on the amplitude and latency of the somatosensory evoked response in monkeys
Authors: Pimmel R. L. , Hung N. C. , Bresnahan J. C. , Hyman P. R. , Yashon D.
Published: January 2005

The effect on the somatosensory evoked response (SER) of the level of anesthesia, and the effect of the site, intensity, duration, and frequency of the stimulus on the amplitude and latency of various components of the SER were studied in 8 Rhesus monkeys. Peroneal nerve stimulation produced similar patterns over both sides of the head, with a slightly larger amplitude over the contralateral cortex. With ulnar nerve stimulation, significantly different patterns were observed over the contralateral and ipsilateral cortex; however, the former still had a slightly larger amplitude. The latency of the various components in the SERs was not influenced by the level of anesthesia or by the intensity, duration, or frequency of the stimulus. As the level of anesthesia decreased, there was a general increase in amplitude of the SERs with peroneal nerve stimulation and no consistent change with ulnar nerve stimulation. The amplitudes of the SER increased with an increase in stimulus intensity or duration, and with a decrease in stimulus frequency.
Response of a brain protein fraction 24 hours after training in rats
Authors: Hydéan Holger , Lange Paul W.
Published: January 2005

The aim of the study was to follow the amount and incorporation of 14C‐valine into separate, soluble protein fractions of the hippocampus, thalamus, and visual cortex of rats from 0 to 72 hr after training. The behavioral test consisted of reversal of handedness with training twice daily for 25 min for 2 days, followed by a 5‐day intermission without training, and a final session of 25 min. The animals were injected intraperitoneally with 14C‐valine 30 min before sacrifice and taken 0, 24, 48, and 72 hr after last training.

After 24 hr, and only at that time, double incorporation values and increased amounts were observed in a protein fraction, No. 6 from the front, in all three brain areas of the trained rats compared to active controls. At 48 hr this protein fraction was at control level.
Endotoxin alters spontaneous transmitter release at the frog neuromuscular junction
Authors: Person Robert J.
Published: January 2005

The direct neurotoxic effects of E. coli endotoxin (ETX) on spontaneous transmitter release were tested at the frog sartorius muscle neuromuscular junction. Spontaneous transmitter release was monitored by intracellularly recording miniature end‐plate potentials (MEPPs). Junctions were continuously exposed to standard concentrations of 10μg/ml of 3 ETX sample, 2 of which produced a significant elevation of MEPP frequency followed by a decline of frequency to very low rates. The third ETX sample, known to have a decreased canine lethality, was with out effect on MEPP frequency. No significant changes in MEPP amplitude were evident. The rate of change in MEPP frequency, but not the peak frequency, was reduced by lowering ETX concentrations. Alterations in MEPP frequency induced by ETX were prevented by removing Ca++ and antagonized by high [k+] out. The results suggest that ETX alters ion conductance channels, particularly those for Ca++, in the presynaptic terminal membrane.
A permanent plastic cannula for intraventricular injections into rat brain
Authors: Mayevsky A. , Gassner S. , Samuel D.
Published: January 2005

The construction and use of a permanent, implanted plastic cannula for intraventricular injections in rat brain is described. The cannula can be used in either acute or chronic experiments.
Binding of apomorphine to neural membranes
Authors: Hoss Wayne , Reese James H. , Smiley Constance
Published: January 2005

The intrinsic fluorescence of apomorphine has been used to measure its binding to neural membranes. A large number of relatively weak binding sites are concentrated in myelin and synaptic membrane fractions. Butyrophenones have the highest affinities for these sites – KD = 43 μM for haloperidol – while dopamine and dopamine releasers and reuptake blockers, as well as a variety of other alkaloids, have much lower affinities. The sites are hydrophobic and undergo a phase transition to a highly fluid state near 26°C. Calcium is a non‐competitive inhibitor of apomorphine binding. Some of the actions of neuroleptic drugs may result from binding to these hydrophobic membrane sites in vivo, blocking conduction in small catecholamine axons.
Transplantation immunity in the brain
Authors: Lodin ZdeněK , HašEk Milan , Chutná Jitka , SláedečEk Miloš , Holáň Vladimír
Published: January 2005

The resistance of animals to allogeneic tumor cells injected into the brain increases with age. The second‐set reaction in the brain of rats appears to be equally effective after preimmunization into the brain and preimmunization into the leg. Also, the presence of cytotoxic antibodies is demonstrable after preimmunization into the brain. These findings suggest that both arcs of the transplantation reaction, the afferent and efferent, are involved in tumor‐cell allotransplantation in the brain.
Electrophysiological, behavioral, and chemical evidence for a noncholinergic, stereospecific site for nicotine in rat brain
Authors: Abood L. G. , Lowy K. , Tometsko A. , Booth H.
Published: January 2005

Pharmacological, electrophysiological, and biochemical studies have been conducted with rats in an attempt to demonstrate that some of the behavioral effects of nicotine may involve non‐cholinergic brain sites. The behavioral response consisted of a prostration‐immobilization syndrome following the injection of 1−10 μg of nicotine into the region of the lateral or third transmitters and their antagonists, and a number of other psychotropic drugs were ineffective in either enhancing or antagonizing the action of nicotine. Associated with the behavioral response were distinct electrophysiological patterns recorded from electrodes implanted in the dorsal hippocampus in freely moving rats. The characteristic electrical changes consisted of shifts in the frequency from 6 to 8 per second to 2 to 4 per second, and shifts in the amplitude from 300 to 400 μV to 100 to 200 μV. A number of derivatives of nicotine and piperidine were synthesized which were found to be antagonistic to the psychopharmacological and electrical effects of nictotine. The natural (−)‐nicotine isomer was found to be at least 100 times as effective as the (+)‐nicotine on the brain. It was not possible to demonstrate 3H nicotine bending to neural membrane preparations; however, the sereospecific nicotine binding was demonstrable in fresh brain slices and to glass filters. The Kb was 2.0 × 10−8M for glass.
Pyridine nucleotide oxidation‐reduction state of the cerebral cortex in the awake gerbil
Authors: Mayevsky Avraham
Published: January 2005

A new approach to study the effect of ischemia on the brain of the awake gerbil is described. The measurement of NADH fluorescence from the surface of the cortex is done by a time‐sharing fluorometer/reflectometer connected to the brain via a flexible light guide and an implanted cannula. The response of the gerbil brain to anoxia and spreading depression is described. By unilateral occlusion of the carotid artery and increase in NADH was measured in the ipsilateral hemisphere.
An X‐ray microanalysis study of differences in concentration of elements in brain cells due to opiates, cell type, and subcellular location
Authors: Cameron Ivan L. , Sheridan Peter J. , Smith Nancy R.
Published: January 2005

Adult female Sprague Dawley rats were divided into three groups and given two daily doses of: 1) morphine (25 mg/kg at each injection), or 2) methadone (5 mg/kg), or 3) saline for nine days. Two hours before the rats were killed on day 10, they were given a double dose of the drugs. Fifteen minutes before being killed, some of the morphine‐treated rats were given the opiate antagonist naloxone (2.5 mg/kg), which caused a sudden arousal in these rats. At the time of killing, the preoptic‐hypothalamic region was rapidly removed and frozen in liquid propane to prevent translocation of elements in cells. Frozen 4‐μm sections were cut, freeze‐dried, and electron‐probed in a scanning electron microscope, and energy‐dispersive x‐ray spectra were collected. The characteristic peak‐to‐continuum ratio for all detectable elements was determined in both the nucleus and the cytoplasm of ependymal cells and neurons. The data from nine cells of each type in each rat brain were then subjected to one‐ and three‐way analysis of variance. The results show significant differences in the distribution of elements (sodium, magnesium, phosphorus, sulfur, chlorine, potassium, and calcium) which are dependent upon: 1) subcellular localization, 2) cell type, and particularly, 3) opiate treatment. The behavioral state produced by the opiate is correlated with the effects they have on intracellular concentration of several elements, most notably, sodium.
Histochemical mapping of acetylcholinesterase and butyrylcholinesterase in the medulla oblongata and pons of squirrel (Funambulus palamarum)
Authors: Bhatt D. K. , Tewari H. B.
Published: January 2005

The distribution of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) has been investigated in a series of sections passing through the medulla oblongata and pons of the squirrel brain. A comparison of the two enzymes has given an interesting picture of their selective localization in the different nuclei. Marked AChE activity has been observed in the cranial nerve nuclei. BChE activity in various nuclei of the medulla oblongata and pons is variable and occurs diffusely between the cells. Possible reasons pertaining to marked variation in AChE and BChE contents of various nuclei and fiber tracts have been discussed.
Choline and phospholipid metabolism and the synthesis of acetylcholine in rat brain
Authors: Jope Richard S. , Jenden Donald J.
Published: January 2005

The metabolism of choline by rat brain, plasma, and liver was investigated using combined gas chromatography mass spectrometry following microwave irradiation and treatment with deuterium‐labeled choline. Methods were established to measure simultaneously the concentrations of six choline‐containing compounds and the incorporation of labeled choline into each of them. Intravenous injection of [2H4]‐choline led to initial labeling of choline, acetylcholine, and phosphocholine in rat brain, with all of the label eventually entering the phosphocholine pool. When labeled choline was administered in the diet its rate of incorporation into choline, phosphatidylcholine, and combined choline plasmalogen and lysophosphatidylcholine in the plasma and liver and into choline, acetylcholine, phosphocholine, glycerophosphorylcholine, phosphatidylcholine, and combined choline plasmalogen and lysophosphatidylcholine in the brain were determined. Choline, phosphatidylcholine, and combined choline plasmalogen and lysophosphatidylcholine in the plasma had similar specific activities. In the cortex and the striatum, choline and combined choline plasmalogen and lysophosphatidylcholine fraction generally had the highest specific activities. The time course of the postmortem release of choline by the brain was measured, and the sources of this choline were, sequentially, acetylcholine, glycerophosphorylcholine, and phospholipids.
Cerebral uptake of nicotine and of amino acids
Authors: Sershen Henry , Lajtha Abel
Published: January 2005

Nicotine is among the compounds that enter the brain very rapidly (blood‐flow‐limited). It also leaves the brain rapidly; by five minutes, 90% exits, an exit somewhat slower than that of water. In spite of rapid exit, brain levels remain higher than levels in blood over a wide range of blood concentrations. Nicotine enters the fetal circulation from the maternal blood; it enters fetal brain but to a smaller extent than adult brain. Nicotine entry is different from that of amino acid: No interaction of amino acid transport and nicotine could be detected. Most close analogs have no effect on nicotine uptake, but at higher concentrations nicotine uptake is saturable. Nicotine and morphine mutually inhibit each other's uptake. The results suggest an uptake compartment (lipid space) for nicotine shared by morphine.
The effect of morphine tolerance on the incorporation of 3H‐leucine into proteins of rat synaptic membranes
Authors: Clouet Doris H. , Ratner Milton
Published: January 2005

The rate of incorporation of 3H‐leucine into proteins of the synaptic junctional and nonjunctional membranes and synaptic vesicles of rat brain has been examined in control and morphine‐tolerant rats. There are no discernible differences between control and tolerant animals in amount of protein as measured by densitometric tracings of dye‐stained proteins separated by acrylamide gel electrophoresis from the three membrane fractions of whole brain areas. However, there are differences in the turnover of membrane protein: three vesicle protein bands and one junctional‐membrane protein band are significantly more highly labeled, and one junctional‐membrane protein is significantly less highly labeled by 3H‐leucine in samples from tolerant rats. Of these, the two junctional‐membrane proteins can be tentatively identified as components of the postsynaptic densities, and one of the vesicle proteins as tubulin.
In vitro formation of neuroglial synapses
Authors: Palacios‐Prü Ernesto , Palacios Laura , Mendoza Rosa V.
Published: January 2005

Neuroglial synapses have been systematically observed in histotypical cerebellar rotary tissue cultures. These axoglial contacts appear as excitatory‐like synapses in which the presynaptic element contains rounded synaptic vesicles accumulated at the presynaptic active zone. The postsynaptic structures were always the somata as well as processes of astrocytic glial cells. The axoglial contacts appear in these cultures when they are prepared from 16‐day‐old chick embryos cerebellum and cultivated during 6 days. To explain these neuroglial interrelationship it has been suggested as a working hypothesis that glial and nerve cells develop plastic capacities in order to establish synaptic contact in the in vitro conditions.
Effects of polarizing currents and repetitive stimulation on the uptake of amino acids by peripheral nerve
Authors: Wheeler Darrell D.
Published: January 2005

The effects of polarizing currents and repetitive stimulation on the uptake of representative amino acids have been studied in peripheral nerve. Glutamic acid, lysine, pheylalanine, and GABA were chosen for study as representatives of different carrier‐mediated transport mechanisms. Depolarizing currents inhibited uptakes of glutamic acid, lysine, and GABA; maximum inhibitions were 56.1%, 20.0%, and 16.7%, respectively. Pheylalanine uptake was not inhibited by polarizing currents under any experimental conditions. Only glutamic acid uptake was inhibited by hyperpolarizing current, with a maximum inhibition of 43.9%. Stimulation had no significant effect on uptake of lysine, phenylalanine, or GABA but was found to potentiate uptake of glutamic acid by 12%.
Uptake of 2‐deoxy‐D‐glucose by cortical synaptosomes from the long—evans rat
Authors: Wheeler D. D. , Hollingsworth R. G.
Published: January 2005

Uptake of 2‐deoxy‐D‐glucose (2‐DG) has been studied in synaptosomes from the Long–Evans rat. Although there are some differences, the results are generally similar to those reported for Sprague–Dawley rats. Both D‐glucose and 2‐DG are taken up by the same carrier, since D‐glucose was found to inhibit uptake of 2‐DG. Uptake is highly dependent on a source of metabolic energy, since incubation at 0°C completely eliminated uptake, while 10−3 M 2, 4‐dinitrophenol (DNP) inhibited uptake by 76.5%.

Uptake has also been measured as a function of both 2‐DG and sodium concentration and the data fitted to a model. Sodium is found to inhibit uptake. A model assuming noncompetitive inhibition by sodium gives best fit to the data. Thus both Kt and apparent Vm are dependent on the sodium concentration. Although these effects are small, Kt increases with [Na], while apparent Vm declines.
Melanotropic peptides: Presence in brain of normal and hypophysectomized rats, and subcellularly localized in synaptosomes
Authors: Loh Y. Peng , Zucker Lloyd , Verspaget Hein , van Wimersma Greidanus Tjeerd B.
Published: January 2005

A major and several minor tricholoroacetic acid (TCA) soluble, bioassayable melanotropic peptides, as well as bioreactive and immunoreactive α‐MSH have been found in the hypothalamus, olfactory bulb and cerebral cortex of normal and hypophysectomized rats. By employing subcellular fractionation procedures it was demonstrated that α‐MSH and the major TCA soluble melanotropic peptide (MMPB) were localized in synaptosomes and were released by hypoosmotic shock. The analysis of MMPB by electrophoretic and chromatographic procedures reveals that it is not ACTH4−10, ACTH1−10, ACTH1−24, NAcACTH1−10 or α‐MSH. MMPB was found to cross‐react with an antiserum specific for the Lys‐Pro‐Val NH2 sequence in α‐MSH, indicating that this C‐terminal sequence of α‐MSH may be present in its structure. MMPB was also shown to differ electrophoretically from the two major TCA soluble melanotropic peptides found in the neurointermediate lobe of the pituitary. In view of their synaptosomal localizations MMPB and α‐MSH may play a role in synaptic function in the nervous system.
Mass spectrometric identification of Cu, Zn, Fe, Co, Mn, Mg, and Pb in mammalian brain
Authors: Hui K.‐S. , Davis B. A. , Boulton A. A.
Published: January 2005

Combining the techniques of thin‐layer chromatography (TLC) and mass spectrometry, we unambiguously identified the trace metals Cu, Zn, Fe, Pb, Mn, Co, and Mg in the brain of a female human who had no evidence of any pathologic disease in the central neveous system, and in brains from mouse, rat, guinea pig, and rabbit. These trace metals were also found in anatomic regions of human brain: cortex (gray), cortex (white), caudate nucleus, putamen, hippocampus, and thalamus, and in anatomic regions of rat brain: hypothalamus, cerebellum, stem striatum, and “the rest.” The metals were characterized from the color and Rf values of their tetraphenylporphyrin chelates on TLC and from the mass and pattern of molecule ion cluster of the mass spectrum. The unexpected presence of lead in the brain is discussed.
Soluble protein and peptide pattern from different regions of rat brain during pre‐ and early postnatal development
Authors: Zeuchner Jenny , Rosengren Lars , Rönnbäck Lars
Published: January 2005

Isotachophoretic pattern from phylogenetically different regions of rat brain during pre‐ and early postnatal development were studied. Four main observations were made: (a) The patterns were greatly similar during maturation of the respective regions studied; (b) One complex of peaks disappeared or decreased in quantity during the 2nd and 3rd weeks of postnatal development; (c) New peaks appeared and accumulated during the same period; (d) Slight differences were observable in the different regions studied.
Membrane fluidity and fatty acid composition of phospholipids in erythrocyte membranes of patients with huntington disease
Authors: Abood Mary E. , Butler Madeline
Published: January 2005

A study was undertaken to determine whether alterations in the configuration of erythrocyte membranes of patients with Huntington disease, reported by other investigators, could be reflected in membrane fluidity‐viscosity. Since membrane fluidity appears to be related to the fatty acid composition of membrane phospholipids, these were also examined. Membrane fluidity, which was determined by measuring the intrinsic fluorescence of membranous tryptophan, was found to be normal. Although the range of fatty acid distribution within the various phospholipids tended to vary somewhat, the pattern was not significantly different from that of the controls.
Relative normophagia and organ growth in growth‐retarded weanling rats with dorsomedial hypothalamic lesions
Authors: Bernardis Lee L. , Bellinger Larry L.
Published: January 2005

Weanling rats with ventromedial (VMNL) and dorsomedial (DMNL) hypothalamic lesions and sham‐operated controls were maintained up to 198 days after operation. Food intake was measured throughout the experiment and organ weights were recorded at various periods of sacrifice. Comparisons were made between controls and VMNL and DMNL rats, respectively. Food intake and organ weights were expressed in absolute terms and relative to body mass and Kleiber's “metabolic size.” VMNL rats were always normophagic and showed lower organ weights, regardless of manner of computation. Rats with DMNL, on the other hand, were absolutely hypophagic but relatively normophagic for considerable periods of time when food intake was referred to body mass. A similar relationship obtained for organ weights. The data fit well with previous results and with a hypothesis that holds that DMNL bring about a “resetting” of some central nervous control system that not only allows the rat so operated to subsist on lower substrate levels but also regulates normal growth in relation to body mass.
Mesencephalic lesions in female rats resulting in normophagia and reduced body weight
Authors: Bellinger L. L. , Bernardis L. L. , Brooks S.
Published: January 2005

The effects of bilateral mescencephalic lesions in the area of the ventral noradrenergic bundle (VNA) were studied in immature and mature female rats. The food intake consumption of the immature lesioned rats did not differ from sham operated controls whether fed a chow or high fat diet.

However, after the surgery the body weights of the two groups began to diverge with the immature lesioned rats obtaining a significantly lower body weight. By the end of the study the immature lesioned rats were also significantly shorter than the controls. Both groups showed normal body composition throughout the measurement period. Upon refeeding after a one day fast the immature female rats defended their lower than normal pre‐fast body weight. These data are in good agreement with our earlier findings using immature male rats. The mature lesioned animals also showed normal food consumption when fed a chow type diet. However the lesioned animals did show a brief hyperphagia when placed on a high fat diet. Unlike the immature lesioned rats the body weight of these lesioned animals did not differ from their sham operated controls. It is suggested that lesions in the area of the VNA may result in hyperphagia or, in no effects on food intake or body weight as reported by others or normophagia with reduced body weight. Exact lesion placement may be responsible for these divergent findings.
Cerebral amino acid levels and uptake in rats after portocaval anastomosis: I. Regional studies in vivo
Authors: Zanchin Giorgio , Rigotti Paolo , Dussini Noemi , Vassanelli Paolo , Battistin Leontino
Published: January 2005

Amino acid levels have been determined in plasma and in four cerebral regions of rats one month after portocaval shunt. Many plasma amino acids are significantly lowered (asparagine, glutamine, threonine, serine, alanine, valine, leucine, isoleucine, cystine, lysine), while others remain unchanged (taurine, glycine, proline, tryptophan, ornithine, histidine, arginine). Asparagine and glutamine levels are significantly higher than in normal rats, and a net increase of tyrosine (100%), phenylalanine (50%) and citrulline (50%) is evident. In the shunted rat brain the most prominent feature is a very large rise (up to fivefold) of tyrosine, phenylalanine, histidine, citrulline, tryptophan, and glutamine uniformly in the tested regions. Other neutral amino acids are slightly increased. Lysine and arginine are decreased in cerebellum and pons‐medulla; taurine, in forebrain and cerebellum.

Cerebral permeability to L‐amino acids was studied in vivo. Neutral amino acid permeability is greatly increased, whereas basic amino acids show a net decrease in their rate of passage from blood to the brain. No changes are observed for GABA and glutamic acid. These data suggest an altered permeability of the cerebral capillary membranes, which seems to be selective for the different amino acid transport classes. Competitive inhibition experiments demonstrate that the increased brain permeability to neutral amino acids after portocaval shunt is due to an enhancement of the saturable transport. The sharp rise in the brain of some essential neutral amino acids (phenylalanine, tyrosine, tryptophan, histidine), largely exceeding their changes in plasma, and the slight cerebral increase of other neutral amino acids despite their lowered level and the rise of competing amino acids in the plasma, is consistent with our observation of enhanced transport for the neutral class.

In hepatic encephalopathy, correction of the altered plasma amino acid levels has been reported to improve the clinical status. If this result is connected to the concomitant correction of the brain amino acid levels, carefully selected competitive inhibition among various plasma amino acids could be a useful therapeutic tool in this pathologic condition. However, the increased activity of the neutral amino acid transport system adds a new factor to the problem, since it probably implies that the competing amino acids will accumulate to unphysiological levels in the brain.
Effects of catecholamines and related compounds on horizontal cells in the fish retina
Authors: Negishi K. , Drujan B. D.
Published: January 2005

The effects of catecholamines (CA) and certain related compounds in the superfusate were examined on the intracellularly recorded potential from horizontal cells in the fish (Eugerres plumieri) retina. The stimulated retinal area consisted of a central spot 1.0 mm in diameter and an annulus 2.0 mm in inner diameter and 4.0 mm in outer diameter; both forms of monochromatic stimuli were centered relative to the recording microelectrode. Each of the CA (dopamine, noradrenaline, and adrenaline) produced an analogous effect on the hyperpolarizing response of all types of horizontal cells. The depolarizing response of the C (R/G)‐type cells was found to change variably with the CA. The effect of dopamine (DA) among the CA was most pronounced when they were used at an equivalent amount. With 10–50 μM, the action of DA was variable but in general its effect was to increase slightly both center and surround responses. In some cases, however, DA initially augmented the surround and reduced the center response. Large amounts of the CA (100–200 μM) augmented the center response and attenuated the surround response considerably; these reciprocal changes usually were associated with moderate depolarization of the cells (5–10 mV). Recovery then occurred in 15–20 minutes. These results indicate that the CA, up to a certain amount, do not directly affect the transmission from photoreceptors to horizontal cells, since the center response became larger. At the same time, the lateral propagation of an S‐potential appears to be selectively affected by the CA, suggesting that the adrenergic system participates in this phenomenon. When an excess of these compounds (200–500 μM) was given, the cells were rapidly depolarized to near 0 mV and eventually the light‐induced responses were abolished. Large amounts (5–10 mM) of metabolic products of the CA (DOPAC and VMA) were found to reduce the center response slightly more than the surround. α‐Methylnoradrenaline, 5‐hydroxydopamine, and serotonin also caused the same but less effect on horizontal cells as did DA. Reserpine and clonidine mimcked the CA effect only if these compounds had been preceded by repeated applications of one of the CA or if the retina had been pretreated with Marplan®. Propranolol, haloperidol, and apomorphine affected neither the horizontal cell membrane potential nor the CA effect. However, phentola‐mine in large amounts (500 μM) markedly diminished the DA action. Therefore, α‐adrenergic receptors appear to he involved in the UA‐induced changes observed in the horizontal cell response.
The effect of morphine and some other narcotic analgesics on brain tryptophan concentrations
Authors: Crossley A. W. A. , Slater P.
Published: January 2005

An acute dose of morphine increased brain tryptophan in mice. This effect was not prevented by naloxone nor was it produced by other narcotic analgesics. Dextrorphan, but not levorphanol, had a similar effect to morphine. A large dose of tryptophan had no effect on the antinociceptive action of morphine in mice. Morphine increased brain tryptophan in rats. This effect was prevented by naloxone. A large dose of tryptophan antagonised the antinociceptive action of morphine in the rat.
Induction of two distinct behavioural responses by chronic treatment with apomorphine
Authors: Kenny Marie , Lynch Marina , Leonard B. E.
Published: January 2005

Male Wistar rats treated with apomorphine (1.0 mg/kg) twice daily for several days exhibited two distinct behavioural responses characterized by stereotyped sniffing or ritualized fighting. The fighting response first appeared on the third day of drug administration and became more severe with repeated treatment. It differed from previously reported apomorphine‐induced aggression [McKenzie, 1971] in that dominant and subordinate rats did not emerge between pairs of fighting rats. Mild defensive fighting occurred in other animals after seven days of drug treatment. Marked differences were observed between aggressive and nonaggressive rats both during the acute effects of the drug and several hours after these effects had worn off. These differences included disturbance in the “open field” behaviour and the reaction to handling. Once a specific behaviour was established in an individual rat, it was not possible to induce a different reaction to apomorphine.

It was shown that, in a group of rats similar in age, sex, strain, and body weight, chronic treatment with a low dose of apomorphine induced distinct and reproducible behavioural patterns. The standard rating scale for apomorphine‐induced stereotyped behaviour was shown to be inadequate for the study of such diverse behaviours.
Tail‐pinch‐induced hyperphagia in weanling rats with dorsomedial hypothalamic lesions
Authors: Bernardis Lee L. , Bellinger Larry L. , Goldman Jack K.
Published: January 2005

Dorsomedial hypothalamic lesions (DMNL) were produced in 26‐day‐old and 44‐day‐old male rats. Sham‐operated rats served as controls. Tail‐pinching (TP) was performed for five minutes at a time over two periods: the first TP period of six sessions each from post‐operative day 1 to day 17 and the second TP period of eight sessions from post‐operative day 18 to day 35. Three equicloric diets, high‐carbohydrate, high‐fat, and high‐protein, were presented ad libitum in pellet form during the TP sessions. Lab chow was available ad libitum in the home cages. Rats with DMNL at age 26 days did not show TP‐induced hyperphagia and HCD preference compared to the controls until the second TP period. In rats lesioned at age 44 days, TP‐induced hyperphagia and HCD‐preference (compared with controls) became evident immediately after the operation. In the home cages (lab chow), DMNL rats showed a decline in food intake from the first to the second TP period, while the sham‐operated controls showed an increase. TP‐induced hyperphagia in the rat with DMNL does not appear to be caused by some arousal‐related process as has been shown for the rat with lateral hypothalamic lesions. Lesions in the nigrostriatal system have been reported to attenuate TP‐induced feeding, while the present study indicates that lesions in the DMN enhance it. This suggests that fibers in the central nervous system may be involved in facilitation or inhibition of TP‐induced eating.
Characterization of unit activity recorded from septum, thalamus, and caudate following incremental opiate treatment
Authors: Dafny Nachum , Rigor Benjamin M.
Published: January 2005

The effects of a wide range of morphine doses and of its antagonist, naloxone, on spontaneous multiunit discharges in freely moving rats were recorded simultaneously from the septum (Spt), medial thalamus (CM‐PF complex), and caudate nucleus (CN). A high percentage of neurons in these three areas are affected by morphine.

Neurons in the CM‐PF complex exhibited a greater number of morphine‐induced changes (104/145) than did those in the caudate nucleus (79/160), or in the septum (67/150).

The morphine‐induced changes exhibited dose‐related patterns: the three structures examined in the present study exhibited four response patterns to incremental doses of morphine: either a monophasic effect, an increase or decrease in firing rate, or a biphasic effect; ie, lower morphine doses induced a decrease in activity, whereas higher doses induced an increase in firing rate.

There was no observed correlation between the response patterns in the three regions. The technique provides a tool with which to identify and classify the specific response patterns induced by morphine in specific brain regions, and the results may indicate that each region plays a different physiological role in the effects induced by morphine.
Chemical requirements of vasopressins for barrel rotation convulsions and reversal by oxytocin
Authors: Abood L. G. , Knapp R. , Mitchell T. , Booth H. , Schwab L.
Published: January 2005

When vasopressin is administred into the lateral ventricles of rats it produces severe convulsive activity characterized by a rapid barrel rotation. Electrical recordings from the dorsal hippocampus indicate marked elevations in the amplitude and frequency at doses of 5 μl of 2 × 10−5 M vasopressin. No significant behavioral effects were noted with oxytocin, somatostatin, β‐melanophore‐stimulating hormone, adrenocorticotropin, or leu‐enkephalin. Pretreatment of the rats with intraventricularly administered oxytocin, β‐MSH, or systemically administered Dilantin prevented the vasopressin‐induced seizures. With the use of chemical and enzymic modification procedures, the essential fragment and amino acids of vasopressin needed for the activity were determined. It was concluded that although the peptide could be acting by vasoconstricting blood arterioles and capillaries in the brain, it may also be exerting a direct excitatory action on neurons.
Neurophysiological evidence for tolerance and dependence on opiates: Simultaneous multiunit recordings from septum, thalamus, and caudate nucleus
Authors: Dafny Nachum
Published: January 2005

Multiunit activity was recorded simultaneously from the septum (Spt), medial thalamus (PF‐CM complex), and caudate nucleus (CN) in freely behaving rats previously implanted with permanent nichrome semimicroelectrodes (62μ in diameter). A challenge dose of morphine (10 mg/kg) and its antagonist (naloxone 1.0 mg/kg) was examined in the same animals while they were morphine naive and after they had become morphine physically dependent. Electrophysiological observations indicated that it would be possible to identify three physiological phenomena: (1) activity related to morphine dependency; (2) activity related to tolerance; and (3) activity related to withdrawal. Experimental observations yielded three different electrophysiological patterns of activity related to tolerance. Each of the three central sites (Spt, PF‐CM, and CN) exhibited a different response pattern to morphine in morphine physically dependent animals.
Accumulation of GFA, the monomeric precursor of the gliofilaments, during development in normal mice and dysmyelinating mutants
Authors: Jacque C. , Lachapelle F. , Collier P. , Raoul M. , Baumann N.
Published: January 2005

Astrocytic reactivity during the myelination period in the mouse was studied with immunochemical method, ie, quantitative determination of the soluble pool of the GFA protein. There is normally a maximum content at the time of early myelinogenesis in any structure; then the GFA level decreases and finally keeps constant for a long period during the adult life. This evolutive pattern is also observed in the dysmyelinating mutant quaking, with a permanent shift toward higher values especially in areas of earlier maturation. In the jimpy mutant, practically devoid of myelin, the increase of GFA occurs but does not stop until death, at 25 days postnatal. This study points out (1) the capacity of astrocytes to synthesize surprisingly high amounts of soluble GFA at periods of intense metabolic activity, and (2) the reactivity of astrocytes in relation to the degree of deficiency of the myelinating oligodendrocytes.
Immunohistochemical localization of the myelin basic protein and of the glial fibrillary acidic protein: Comparative study in normal, quaking and jimpy mice
Authors: Dupouey P. , Lucas C. V. , Gomes D. , Jacque C.
Published: January 2005

The topographical distribution of myelin basic protein (MBP) and of glial fibrillary acidic protein (GFA) have been compared in the CNS of 18‐day‐old normal, quaking, and jimpy mice using indirect immunofluorescence. Comparison was made in brain and spinal cord sections. MBP was strongly decreased in quaking and jimpy mice in all parts of the CNS. A pronounced gliosis was observed in jimpy mice with occurrence of numerous hypertrophied astrocytes. To a lesser extent, an astrocytic reaction was also observed in quaking CNS.
Intraventricular ACTH and vasopressin cause regionally specific changes in cerebral deoxyglucose uptake
Authors: Dunn Adrian J. , Steelman Suzanne , Delanoy Richard
Published: January 2005

The cerebral uptake of subcutaneously injected [3H] 2‐deoxyglucose (2DG) was used to determine regional changes of cerebral glucose uptake associated with peptide‐induced behaviors in mice. Evidence is presented that the use of [3H] 2DG (s.c.) gives results qualitatively similar to those obtained using intravenous [14C] 2DG. Lysine vasopressin, 1 μg intracerebroventricularly (i.c.v.), induced the characteristic hyperactivity previously described, and significantly decreased [3H] 2DG uptake in frontal cortex. ACTH1−24 (1 μg, i.c.v.) induced excessive grooming and concomitant decreases in [3H] 2DG uptake in olfactory bulb, pyriform cortex, and amygdala, and an increase in cerebellum. These results are only partly consistent with previous results on the cerebral sites of action of ACTH and vasopressin. These patterns of 2DG uptake are distinct from those observed following footshock, indicating that the peptide hormones mediate the effects of footshock on [3H] 2DG uptake only partially if at all.
Poly(A)‐ and nonpoly(A)‐RNA associated with rat brain microsomal fractions: In vivo labelling studies
Authors: Czosnek Henryk , Soifer David , Gal Alma , Mack Kathryn , Hochberg Abraham , Wisniewski Henryk M.
Published: January 2005

The time course of incorporation of radiolabelled precursor into RNA associated with rat brain free polyribosomes, rough membranes, and smooth membranes was measured following a single intracranial injection of [3H] orotic acid. Polyadenylated RNAs were separated from nonpolyadenylated RNAs by affinity chromatography on oligo (dT)‐cellulose columns. Poly(A)‐RNA associated with each of the microsomal fractions became more rapidly labelled than did the nonpoly(A)‐RNA of the same fractions. While the labelling profiles of the nonpoly(A)‐RNA isolated from the polyribosomes and rough membranes are similar from one fraction to another, the specific radioactivity of the poly(A)‐RNA isolated from free polyribosomes increased much more drastically than that of the poly(A)‐RNA associated with rough membranes. The labelling profiles of RNA species isolated from smooth membranes were very different in this respect from the two ribosomal fractions. There was a lag of more than four hours before significant label appeared in the RNA associated with the smooth membrane fraction. These studies demonstrate that the different populations of brain microsomal RNA are labelled at different rates, perhaps reflecting differences in the turnover of these RNAs and differences in their function.