摘要:

AbstractForCalliphorathe wingbeat frequency and the underlying motoneuronal activity were recorded during adult life. Wingbeat frequency increases during the ten days following last molt. The activity of motoneurons serving four selected flight muscles (nonfibrillar and fibrillar ones) also increases with age. The motoneuronal activity of young and old flies was analyzed statistically (serial and cross‐correlograms, latency and phase histograms). In addition, several wing manipulations were carried out to evaluate the significance of sensory feedback on pattern generation during maturation. These ontogenetic studies suggest a centrally generated motor pattern that (1) is essentially complete with the molt to adulthood, (2) shows a progressive increase in intrinsic activity, and (3) is modulated by sensory feedback from the wing region by the same amount irrespective of age. Similarities in the postlarval development of the flight pattern of neurogenic and myogenic flyers are discusse

ISSN:0022-3034    

DOI:10.1002/neu.480120102

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe fast axoral transport of proteins was studied in the cat sciatic nerve after injection of [3H] leucine into the spinal ganglion or the ventral horn of the seventh lumbar segment. The amount of transported proteins after ganglion injection was linearly related to the amount of label present at the ganglion. At variable intervals after ganglion or spinal cord injection, the sciatic nerves were sectioned in some experiments. The transport of proteins continued in the peripheral nerve stump in a wavelike manner, but the advancing wave leaves a labeled trail behind. A fraction of this trail corresponds to proteins moving at slower velocities than thevelocity of proteins in the wave front. Another fraction of the trail corresponds to molecules retained by the axons. Each nerve segment of 5 mm in lenth retains 1.5% of the transported proteins, and the profile of retained proteins along the sciatic nerves follows a single exponential function. From the proportion of retained proteins, the concentration of transported proteins at the terminals of branching axons as a function of the branching ratio was estimated. In the case of motor axons innervating the soleus muscle of the cat, the concentration of recently transported proteins at the nerve terminals would be approximately 0.83% of the proteins leaving the spinal cord. This low concentration of transported proteins at the nerve terminals may explain the lability of neuromuscular synapses when axonal transport is decreased or interrupted.

ISSN:0022-3034    

DOI:10.1002/neu.480120103

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

年代:1981

数据来源: WILEY

摘要:

AbstractIn this article we report that the distribution of serotonin in the lobster nervous system parallels the distribution of octopamine and that the same tissues that contain endogenous serotonin can synthesize it from tryptophan. Octopamine and serotonin are highly concentrated in a neurosecretory region of the second thoracic roots in association with a group of neurosecretory cells. The roots possess separate high‐affinity uptake systems for both serotonin and tryptophan. Radioactive serotonin, accumulated in tissues during incubations with either tritiated serotonin or tritiated tryptophan, can be released, in a calcium‐dependent manner, by depolarization with potassium. A detailed morphological examination of the second thoracic roots shows four distinct categories of nerve endings in the vicinity of the neurosecretory cells. Octopamine is synthesized in one of these types of endings and serotonin in another. The high‐affinity uptake systems for serotonin and tryptophan are found only in association with the endings that make serotonin. These endings and all the biochemical parameters of serotonin metabolism in the roots are selectively destroyed by previous injection of animals with the neurotoxin 5,7‐dihydroxytry

ISSN:0022-3034    

DOI:10.1002/neu.480120104

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe compound eye of the praying mantis is covered with approximately 600 bristles and campaniform sensilla. Their afferents project to the brain, and to the suboesophageal and prothoracic ganglia. Cutting the eye branch of the dorsal tegumentary nerve (DTN), the peripheral nerve innervating the corneal sensilla, makes it impossible to initiate head grooming by tactile stimulation of the eye. This stimulus is a strong releaser of grooming behavior in normal animals. Head grooming can be initiated, after cutting the eye branch of the DTN, by stimulation of the frons (the operation leaves the sensory innervation of this part of the cuticle intact). Frame‐by‐frame analysis of films of head grooming after cutting the nerve reveals a reduction of the speed at which the forelimb is brushed across the surface of the head and eye. The significance of this finding is discussed in terms of a putative feedback loop from the corneal sensilla to the motor neurons controlling the grooming moveme

ISSN:0022-3034    

DOI:10.1002/neu.480120105

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

年代:1981

数据来源: WILEY

摘要:

AbstractRat brain synaptic plasma membranes contain two receptorlike binding sites for the inhibitory transmitter γ‐aminobutyric acid. Postsynaptic junctional structures (postsynaptic densities) isolated from these membranes contain only the higher affinity site enriched more than sixfold compared to the membranes. The results provide the first direct evidence for the association of transmitter receptors with postsynaptic junctional sites in the bra

ISSN:0022-3034    

DOI:10.1002/neu.480120106

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe action of colchicine, a drug known to disrupt microtubules, on synaptic transmission and voltage‐dependent phenomena was studied. Colchicine depressed transmission in both cholinergic and noncholinergicAplysiaganglionic synapses. In some synapses, this effect was partly due to the curare like properties of the alkaloid. Ca2+currents, analyzed by voltage clamp techniques, were rapidly depressed by intracellular injection of colchicine and more slowly depressed by external application. Injected colchicine acted at much lower concentrations than required extracellularly. The implication of the reduced calcium influx in synaptic transmission is discussed. Colchicine caused a shift in the reversal potential of acetylcholine‐activated chloride channels in a direction consistent with an increased intracellular chloride activity. It was concluded that the wide range of actions of colchicine on membrane properties should be taken into account when this drug is used in biological resea

ISSN:0022-3034    

DOI:10.1002/neu.480120107

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

年代:1981

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480120108

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

年代:1981

数据来源: WILEY

摘要:

AbstractWe show that the “escape response” (running) of the cockroachPeriplaneta americanais interrupted when the insect runs through a shadow. Shadows were cast by holding an opaque plastic sheet so that the cockroach ran beneath it. In control experiments, a similarly positioned clear plastic sheet was ineffective. Removal of the shadow stimulus allowed running to continue. The likelihood that cockroaches would resume running after removal of the shadow stimulus decreased with the time they were allowed to remain in sha

ISSN:0022-3034    

DOI:10.1002/neu.480120109

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

年代:1981

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480120110

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

年代:1981

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480120101

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

年代:1981

数据来源: WILEY