摘要:

AbstractResponses to the sinusoidal modulation envelopes of amplitude‐modulated tone and noise carriers were recorded from single units in the cochlear nucleus of the cat. The unit discharges were synchronized to the peaks of the modulation envelope. Population‐averaged firing rates were independent of the modulation index of the stimulus. Temporal firing patterns, as represented by the shapes and magnitudes of modulation‐cycle histograms, were strongly dependent on stimulus intensity and modulation index. Nonlinear nonsinusoidal responses to sinusoidal modulation envelopes were observed, but only at very high values of sound intensity. These and other results are discussed in the context of psychological studies concerning the perception of speech inform

ISSN:0360-4012    

DOI:10.1002/jnr.490020502

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

年代:1976

数据来源: WILEY

摘要:

AbstractAnalysis of in vitro vs in situ development of Purkinje cells was undertaken in order to compare the transitory morphology of Purkinje cells grown in situ with their differentiation in vitro. Purkinje cells in rotary cultures developed their basic morphological pattern only when the cultures were prepared from 16‐day chick embryos, indicating the existence of a critical period during their normal differentiation, which lasted approximately 24 hr between days 14 and 15 of embryonic developmen

ISSN:0360-4012    

DOI:10.1002/jnr.490020503

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

年代:1976

数据来源: WILEY

摘要:

AbstractLabeling of cyclic AMP of taste papillae and its responsiveness to taste stimuli has been measured using whole papillae from bovine tongue prelabeled with [8‐14C] 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 m

ISSN:0360-4012    

DOI:10.1002/jnr.490020504

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

年代:1976

数据来源: WILEY

摘要:

AbstractA time‐decay colchicine‐binding assay was used under optimal conditions for measuring tubulin concentration in the cerebral cortex and cerebellum during postnatal development. In both brain areas soluble tubulin concentration (pmoles colchicine bound/mg tissue) declined by about 35% between 4 and 12 days of age after which the decrease was more gradual up to adulthood. Colchicine‐binding protein concentration of particulate fractions, on the other hand, increased between 4 and 12 days of age followed by relatively little change. The concentration of tubulin the soluble and particulate fractions of the cerebral cortex was 45% and 75% greater, respectively, than corresponding fractions of the cerebellum. The expression of tubulin on the basis of DNA, revealed marked regional differences which can be considered a reflection of differences in the relative extent of morphological differentiation in these areas during the postnatal period. Tubulin in both soluble and particulate fractions exhibited a marked increase in lability for colchicine binding from approximately 12 days of age. The half‐life for loss of colchicine‐binding activity was 2.5‐fold greater in particulate colchicine‐binding reaction provides additional support for the hypothesis that it represents a functionally significant association of tubulin with membrano

ISSN:0360-4012    

DOI:10.1002/jnr.490020505

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe 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.

ISSN:0360-4012    

DOI:10.1002/jnr.490020506

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

年代:1976

数据来源: WILEY

摘要:

AbstractBilateral electrolytic lesions were placed in the dorsomedial hypothalamic nuclei (DMN) of weanling male Sprague‐Dawley rats. Sham‐operated rats served as controls. After 22 days on lab chow and tap water ad libitum, the animals were injected with U‐14C‐alanine 0.167 μC/μ moles intraperitoneally (5 μC and 30 μ moles/100 gm body weight) and sacrificed 2 hr later. There was no significant difference, in the incorporation of the label into total lipid, free fatty acids, glycogen, or tissue protein of both liver and diaphragm, between the DMN‐lesioned and the sham‐operated rats. Similarly, there was no significant difference in the incorporation into the plasma glucose or protein. It is concluded that in spite of profound alterations in both ponderal and linear growth and food intake, there is no disruption of normal gluconeogenesis in the weanling rat w

ISSN:0360-4012    

DOI:10.1002/jnr.490020507

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

年代:1976

数据来源: WILEY

摘要:

AbstractSixty percent of the dopamine β‐hydroxylase (DBH) (EC 1.14.2.1) activity in rat brain was found to be bound to membrane fractions. The additions of Triton X‐100 solubilized DBH completely and permitted the estimated of the total enzyme activity. In homogenates the DBH could be detected in the absence of Triton X‐100 but was 30–45% of this total enzyme activity; in crude synaptosomal fractions this value was only 10%. Incubation of brain slices in media containing 2 × 10–3M acetylcholine (ACh) led to an increase by a factor of 2–2.5 in the activity of DBH measured in the absence of detergents; however, total enzyme activity remained the same. The addition of 6 × 10–2M K+in place of ACh produced a similar effect; however, the increase in the activity of DBH measured in the absence of detergents was only 25%. The effect of ACh could be reversed by removing it from the medium, or by the addition of diethyl p‐nitrophenyl phosphate (paraoxon) 4 × 10–5M. The addition of eserine 4 × 10–4M increased the effect of ACh at 15 min of incubation. Neither acetate nor choline had any effect. Intact cell boundaries appeared to be necessary, since addition of ACh after complete homogenization caused no increase in activity. ACh caused a (9–10)‐fold increase in the specific activity of membrane‐bound DBH but no change in the specific activity of the enzyme in cytosol. Although the effect of ACh mimicked the effect of Triton X‐100, it was not due to the solubilization of DBH. The presence of ACh did not increase the release o

ISSN:0360-4012    

DOI:10.1002/jnr.490020508

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

年代:1976

数据来源: WILEY

摘要:

AbstractThe activity of CTP synthetase (UTP: ammonia ligase (ADP, EC. 6.3.4.2.)) was determined in rat cerebral hemispheres and cerebellum during postnatal development. It was found that enzyme activity, when expressed per unit of protein or wet tissue weight, in both parts of the brain decreased with age, the diminution proceeding more rapidly in the cerebellum than in the hemispheres. When CTP synthetase was expressed on the basis of DNA an activity peak in the hemispheres with a maximum on the 5th day after birth was observed. The enzyme content per cell was several times lower in the cerebellum than in the hemispheres at each age studied, with the exception of 1‐day‐old animals, in which both tissues displayed intensity of RNA synthesis in the developing brain. The conclusion was reached that the changes of CTP synthetase activity were closely related to the RNA metabolism. Therefore the enzyme under study may be one of the factors involved in cell control of RNA synthe

ISSN:0360-4012    

DOI:10.1002/jnr.490020509

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

年代:1976

数据来源: WILEY

摘要:

AbstractInterrelations in the apical dendrite bundles of a single neuronal column were revealed by means of light and electron microscopy in the cat motor cortex. Such column presents an integrated structural module. There were also found wider joinings of several columns, among which complex coordination may exist.

ISSN:0360-4012    

DOI:10.1002/jnr.490020510

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

年代:1976

数据来源: WILEY

摘要:

AbstractStereospecific opiate binding has been demonstrated in human erythrocyte membranes, having a Kdof 9 · 10–9M. In most respects the binding characteristics resemble those of snyaptic membranes. These included the correlation of binding affinity and pharmacological potency of opiates; competition by naloxone; inhibition by Ca2+and Na+; and sensitivity to phospholipases and tryspin. A comparison of stereospecific opiate binding in control human subjects and heroin addicts revealed a 43% increase in the addict gro

ISSN:0360-4012    

DOI:10.1002/jnr.490020511

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

年代:1976

数据来源: WILEY