摘要:

AbstractThe method of Aghajanian and Bloom (1967) was applied to the visual cortex of normal and neonatally visually deprived rats. The rats were kept with their mothers in total darkness since birth, in a ventilated and temperature‐controlled animal quarter. Controls were rats from the same stock, maintained in a regular 12‐h‐light/12‐h‐dark rhythm. The animals were killed at 15, 23, 40, and 65 days of age, and the visual cortices fixed in 4% glutaraldehyde and processed for electron micrography with ethanol‐phosphotungstic acid. A total of 6249 synaptic profiles were counted and their numerical density (DS) determined in both conditions. Features of the presynaptic grid were used for classifying the synaptic profiles in: type A [with one presynaptic dense projection (PsDP)]; type B (with two or three PsDPS); and type C (with four or more PsDPS). In the visually deprived rats the DS increases with a rate similar to controls, but the values for each age are slightly lower (P>0.01). Type B synapses predominate in the visually deprived group while types A and C are scarcer. The differences found between types were maximal at 65 days of age and the results were highly significant (P>0.001). It is concluded that major effects of dark‐rearing are manifested when the individual features of the presynaptic grid are considered. It seems that a selected population of synapses is affected by the alteration of the normal epigenetic influence of early visu

ISSN:0022-3034    

DOI:10.1002/neu.480140102

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe level of calcium‐activated neutral protease (CANP) activity in the brain and nerve cord of the crayfishProcambarus clarkiiwas assayed by measuring the degradation of casein yellow by tissue homogenates. When care was taken to maintain the ionic strength of all incubation media at 0.15Mand to buffer the Ca2+activity of the media with 5mMEGTA, CANP was found to be very sensitive to Ca2+; maximal activity was achieved at 1 × 10−3MCa2+, with 50% of this maximum present at the physiologic intracellular Ca2+activity of 1 × 10−7M. We found that the anticonvulsant agent phenytoin was without effect on CANP activity while pentobarbital and a relatively new anticonvulsant agent, valproic acid (an eight‐carbon branched fatty acid), significantly inhibited CANP activity in a dose‐dependent manner. The inhibitory effect of valproic acid was shared by a straight‐chain eight‐carbon fatty acid, caprylic acid. These findings demonstrate that inhibition of CANP activity is not limited to agents with a specific molecular structure. They also suggest that CANP plays a role in the normal turnover of proteins that control various cel

ISSN:0022-3034    

DOI:10.1002/neu.480140103

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe spiny lobster stomatogastric ganglion has been shown to be innervated by catecholaminergic processes which derive from cells of large central ganglia (Kushner and Maynard, 1977). Biochemical evidence had indicated that the stomatogastric system synthesizes dopamine and not norepinephrine from tritiated tyrosine (Barker, Kushner, and Hooper, 1979). Studies reported here document that the stomatogastric ganglion itself contains dopamine, as measured with a sensitive endogenous assay. Moreover, the ganglion can synthesize dopamine from tritiated tyrosine or DOPA. Additionally, when incubated in tritiated dopamine, the ganglion takes up dopamine and protects it from degradation; this process is inhibited by cocaine. When incubated with3H‐tyrosine, small but measurable amounts of tritiated dopamine were detected in the medium surrounding the ganglio

ISSN:0022-3034    

DOI:10.1002/neu.480140104

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe snail tentacle ganglion is a prominent structure that innervates an epithelial pad sensitive to wind and odors. Its neural composition, and that of the sensory pad, was studied in the terrestrial snailAchatina fulicaby applying horseradish peroxidase to the distal end of the cut tentactle nerve. Five types of neurons were labelled by the procedure: receptors, located in the subepithelial region; three kinds of interneurons, located in the ganglion and its digitlike extensions; and a bipolar neuron, located in the dermo‐muscular wall of the tentacle. In contrast to earlier descriptions based on silver stains, the present results demonstrate the presence of neurons of large size (soma diameters up to 46 μm). Also, contrary to earlier interpretations, the results indicate that all five identified cell types send axons directly to the C

ISSN:0022-3034    

DOI:10.1002/neu.480140105

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

年代:1983

数据来源: WILEY

摘要:

AbstractThis study examined certain structural and functional aspects of the olfactory system in regenerated posterior tentacles of the terrestrial snailAchatina fulica.Regeneration of the epithelial sensory pad occurs with accurate size regulation. All five neuronal cell types which are normally revealed by horseradish peroxidase backfilling are also regenerated. The sensory cells attain normal numbers at about 20 weeks postlesion. The organization of neuronal elements within the tentacle is chaotic, however, at early stages of regeneration. Even later, the digitlike extensions of the ganglion, which are characteristic of intact tentacles, fail to appear. The recovery of odor sensitivity was evaluated using a tentacular olfactometer and a behavioral assay that involved locomotor orientation towards the odor stimulus. Thresholds and concentration‐dependent response rates were equivalent for regenerated and intact tentacles, tested in the same animals, at 10 weeks post‐les

ISSN:0022-3034    

DOI:10.1002/neu.480140106

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe cardiac ganglion fromHomarus americanuswas investigated for the purpose of providing biochemical and histochemical information as to the identity of the neurotransmitter(s) utilized by this system. Three techniques were employed in this study: (1) the glyoxylic acid histofluorescence staining technique (GA), which showed fluorescence characteristic of catecholamines localized in the five motor neurons; (2) high‐voltage electrophoresis (HVE) in one dimension followed by ascending chromatography in the second dimension, which indicated incorporation of label from tritiated tyrosine into norepinephrine (NE) and small amounts of dopamine (DA); (3) high‐pressure liquid chromatography with electrochemical detection (HPLC/EC), which indicated the presence of endogenous norepinephr

ISSN:0022-3034    

DOI:10.1002/neu.480140107

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

年代:1983

数据来源: WILEY

摘要:

AbstractTo determine whether axonal transport plays a role in the establishment of long‐lasting changes in synaptic transmission, the effects of colchicine on transport and on synaptic modifications induced by hyperactivity were studied in the nerve cord of the cockroachBlatta orientalis. Application of a lead weight on the insect′s dorsum, and the consequent exaggerated use of antigravity reflexes, facilitated synaptic transmission along a particular nervous pathway in the metathoracic ganglion. Application of colchicine in the prothoracic ganglion reversibley blocked such synaptic facilitation and temporarily interfered with the transport of proteins along the cord. Five components of axonal transport, moving at 2, 10, 25, 75, and 150 mm/day, were altered by colchicine treatment with a temporal course that coincided with the reversible inhibition of synaptic facilitation. These results were brought about by colchicine acting directly on axonal transport at the level of the prothoracic ganglion, rather than on synaptic transmission measured at the metathoracic ganglion. The temporal correlation observed between the effects of colchicine on axonal transport and on synaptic facilitation strongly suggest that the transport process is essential for long‐lasting synaptic modifications to take

ISSN:0022-3034    

DOI:10.1002/neu.480140108

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

年代:1983

数据来源: WILEY

摘要:

AbstractSynapses in explant cultures of fetal rat neocortex at day 18in vitrowere stimulated by veratridine (10−4M) for 20 min. The cultures were subsequently processed for electron microscopy and the synapses were analyzed by quantitative techniques, incorporating set mathematical treatment. The mean values of area, perimeter, and form factor of the presynaptic elements significantly increased following veratridine stimulation, compared to the values of control synapses. The length of the postsynaptic thickening also increased, while synaptic curvature did not change significantly in the veratridine group. A fivefold reduction was observed in the mean number of synaptic vesicles per presynaptic element and in the vesicle‐terminal area ratio, following veratridine stimulation. The cytoplasm‐terminal area ratio and the occurrence of vacuoles/cisternae significantly increased after veratridine application. Planar measurement of membranes (boundary length) of different presynaptic organelles revealed that the total membrane did not change significantly in the veratridine group. The data indicated an increase in volume and swelling of the pre‐ and postsynaptic elements, considerable depletion of synaptic vesicles, and preservation of the total presynaptic membrane following veratridine stimulation in nerve tissue

ISSN:0022-3034    

DOI:10.1002/neu.480140109

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

年代:1983

数据来源: WILEY

摘要:

AbstractColchicine (4 μg), injected into the fifth lumbar (L5) dorsal root ganglion of the rat, preferentially inhibited tubulin transport with little, if any, effect on the transport of other slowly migrating proteins. This inhibitory effect of colchicine on slow axonal transport persisted at least two days after the treatment, but no more than four days. Within these days the damaged axons were recovered to start regenerating with the rate of 4.7 ± 0.1 mm/da

ISSN:0022-3034    

DOI:10.1002/neu.480140110

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

年代:1983

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480140111

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

年代:1983

数据来源: WILEY