摘要:

AbstractThe occurrence and distribution of serotonin (5‐HT) and amino acids along the central nerve chain of the leech, Hirudo medicinalis, was analyzed using dansylchloride in order to obtain information on the functional roles of amines and amino acids. There was no statistical variation in the occurrence of most of the amino acids or serotonin in the different parts of the dorsal nerve chain of the leech. A variation in the serotonin content was found during the year with the highest level occurring in winter. Leech ganglia also accumulated3H‐tryptophan and metabolized part of it to form 5‐HTP, 5‐HT, and 5‐HIAA. The resutls are discussed from the point of view of 5‐HT being a transmitte

ISSN:0360-4012    

DOI:10.1002/jnr.490020102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractIn adult rats, using the single‐pass brain uptake technique with a tritiated water standard, L‐phenylalanine was shown to enter brain across the blood‐brain barrier (BBB) by both a saturable and diffusionary process. A kinetic analysis of the data revealed Michaelis constant (Ka) of 0.42 mM and Vmaxof 35 nmoles g−1min−1The saturable component of L‐phenylalanine transport was adversely affected by dinitrophenol or low sodium concentration in the intracarotid injection solution. Intravascular ouabain did not affect transport and only partial inhibition was observed with 1.5 mM L‐leucine. It appears that there is no regional difference in the capacity of the BBB to more L‐phenylalanine from blood to brain. This process is directly or indirectly coupled to sodium movement and is partially dependent on

ISSN:0360-4012    

DOI:10.1002/jnr.490020103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractBioelectric activities of hypothalamic dendrites of newborn kittens and adult cats were recorded in vivo. Stimulation of various hypothalamic areas with electrical stimuli, or by injection of norepinephrine, generated propagated spikes in both new‐born and adult neurons. The morphologically immature hypothalamic dendrites were hypersensitive to stimuli and were able to generate propagated spikes not only of axon hillock (adults) but also of dendritic membrane origin. Some mechanisms responsible for the two types of spike formation (newborn and adult) have been identifie

ISSN:0360-4012    

DOI:10.1002/jnr.490020104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractLesions in either olfactory bulb or in area postrema modify the amphetamine‐induced paradoxical thermoregulatory behavior, although these lesions in no way affect amphetamine‐induced hypothermia. In addition, these lesions lead to complicated patterns of thermoregulatory behavior. These results can be best explained by assuming that lesions in one part of the brain monoamine system might affect levels and turnover of monoamines in remote parts of the brain. Among d‐amphetamine behavioral effects which are known to be mediated by central dopaminergic neurons are hypothermia in animals placed in a cold environment, and paradoxical thermoregulatory behavior (this involves the movement of animals away from the heating source despite hypothermia). This latter effect requires intact alpha norepi‐ nephrine receptors. It seems that neither type of lesion affected dopaminergic neuronal activity in the brain. However, norepinephrine activity in the brain was affected by the area postrema lesion as well as by the olfactory bulb

ISSN:0360-4012    

DOI:10.1002/jnr.490020105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe effect of the chronic administration of α‐MSH on the incorporation of tritiated tyrosine into noradrenalin and dopamine and of tritiated tryptophan into serotonin was studied in different regions of the rat brain. α‐MSH increased the incorporation of tritiated tryptophan into serotonin in the cortex and slightly decreased that of tyrosine into the dopamine in the hypothalamus. As the brain concentration of serotonin was unchanged in the animals treated with α‐MSH, it is suggested that some of the changes in behavior, which other investigators have found following the administration of peptides containing the same sequence of amino acids to that found in MSH, could be associated with an increased turnover of cortical s

ISSN:0360-4012    

DOI:10.1002/jnr.490020106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractTwenty mature male Sprague‐Dawley rats were lesioned in the area of the ascending ventral noradrenergic bundle in the mesencephalon. Nine sham‐operated animals served as controls. Food intake between the lesioned and nonlesioned groups was not significantly different except for the first day post surgery. However, body weight of the lesioned group was significantly below that of the controls when measured 15 days after the operation. The lesioned animals weighed significantly less than the controls throughout the rest of the experiment. They also were hypoactive when compared to the sham‐operated rats. Control rats and lesioned rats did not differ significantly in deep rectal temperature.It is suggested that the significant decrease in body weight of the lesioned rats in the presence of normophagia may be caused by alterations in the animal's metab

ISSN:0360-4012    

DOI:10.1002/jnr.490020107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThis review presents an analysis of the sensory and motor mechanisms as they are now understood that cause the immobility reflex (IR). Of the sensory systems that conceivably could trigger and sustain the IR, as commonly induced experimentally by inversion and manual restraint, evidence has been presented to eliminate some senses (vestibular, vision, sound, many visceral sensations, olfaction, taste, temperature), while incriminating tactile and proprioceptive influences. Of the motor systems which could cause the profound immobility during IR, neurosurgical and electrophysiological evidence identifies the locus of the inhibitory neurons in the brain stem and/or spinal cord.The evidence reviewed leads to a unified working hypothesis of IR mechaisms. IR is considered to be caused by a group of neurons in the brain stem which inhibit spinal motoneurons, either directly or indirectly, when those inhibitory neurons are activated by a specific pattern of tactile and proprioceptive input.Modulation of the IR control system appears to come from the limbic system, which under fear‐producing conditions, potentiates the IR in part by release of epinephrine. Inhibition of the IR control system appears to come from the neocortex, as well as the brain stem reticulum, when it is activated by nonspecific, arousing somaesthetic sensations that produce generalized activation of the neocortex and skeletal muscl

ISSN:0360-4012    

DOI:10.1002/jnr.490020108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractA study was conducted on the adsorption of 14C‐ATP to a surface film of a hydrophobic protein derived from synaptic membranes isolated from bovine cerebellum. The adsorption of ATP to the protein film followed a rate law based on diffusion and an energy barrier to adsorption, the rate law being generally applicable to the adsorption of ions to a charged interface. Studies were also carried out on the displacement of ATP from the film by the injection of other nucleotides, inorganic phosphates, and other anions. The kinetics conformed to a rate law based on diffusion and displacement. The most important factor in the displacement of ATP was the magnitude of charge of the anion, while steric factors were relatively minor. However, from a consideration of the energy barrier to adsorption it appeared that steric factors play a greater role in the adsorption of ATP. The results are discussed in relationship to the configurational aspects of the surface film as well as their possible significance in synaptic functio

ISSN:0360-4012    

DOI:10.1002/jnr.490020109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe frontal cortex showed a marked elevation of incorporation of H‐L‐fucose into glycoproteins of the crude synaptosomal fraction at 9 days of age. The effect was observed at both 8 and 24 hr after intraperitoneal administration of radioactive fucose. The elevation was absent in the 1, 5, 16, and 25‐day‐old frontal cortices. It was also absent in the hippocampus and cerebellum at all ages studied.Fucose‐labeled glycoproteins of high molecular weight in the crude synaptosomal fraction, as separated by polyacrylamide gels, were preferentially labeled in the hippocampus, frontal cortex, and cerebellum at all ages studied. In general, these glycoproteins became less prominent in the oldest animals studied (25 days). However, the relative amount of these glycoproteins varied with age of the animal, time between administration of isotope and sacrifice, and with the brain area

ISSN:0360-4012    

DOI:10.1002/jnr.490020110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

ISSN:0360-4012    

DOI:10.1002/jnr.490020111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY