摘要:

AbstractResponses of cercal “bristlelike” hair sensilla (BHS) onPeriplaneta americanaL. to movement were investigated by recording generator (GP) and spike potentials with an extracellular pipette electrode which held the bristle by its tip. BHSs had no resting discharge, were purely phasic, with sensitivity only to stimulus transitions. They were directionally sensitive. Sinusoidal analysis suggested, to a first approximation because of the important nonlinearities, the behavior of a first‐order lead system with corner frequencies distributed between 8 and 20 Hz. Responses elicited by step‐ and ramplike displacements were roughly in accord with the above behavior. Nonlinearities occurred both at GP level and at the level of spike generation. The phasic and the nonlinear behaviors at GP level may have a mechanical origin. The lack of spontaneous activity and the threshold nature of the spike generator account for other nonlinearities. The operation of BHS could be separated conceptually into a linear element followed by nonlinear elements. A computer simulation based on these concepts showed a close fit to the biological re

ISSN:0022-3034    

DOI:10.1002/neu.480120202

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

年代:1981

数据来源: WILEY

摘要:

AbstractInput‐output (I‐O) relationships were studied in cercal “thread‐hair” sensilla (THS) onPeriplaneta americanaL. by recording from individual axons of THS while displacing the corresponding hair with a galvanometric device. Sinusoidal analysis was attempted and pulse‐ and ramplike displacements were then tested. The effects of stimulus orientation were also investigated. THS were spontaneously active and purely phasic and did not respond to sustained displacements. With small sinusoidal displacements (<30°) they behaved as a linear, secondorder lead system sensitive to velocity. With larger amplitudes, however, they exhibited prominent nonlinear features with minimal consequences of displacements at the extremes. Responses to other waveforms indicated secondorder response components. THS were directionally sensitive. Phasic behavior and the nonlinearities may be due to mechanical properties at the base of the hair. The spike‐firing threshold may also contribute. Resting activity appears to be due to neuronal factors since it was not abolished by preventing hair movements. Transducer operations were simulated in a di

ISSN:0022-3034    

DOI:10.1002/neu.480120203

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe release of hyperlipemic hormone from the glandular cells of the corpus cardiacum (CC) ofLocusta migratoriais under the synaptic control of axons in nervus corpus cardiacum II (NCC II). The effects of aminergic agonists and antagonists on the release of the hyperlipemic hormone induced by electrical stimulation of NCC II have been examined. CC isolated from reserpine‐injected locusts did not release hormone when subjected to electrical stimulation of NCC II but continued to release hormone in response to high‐potassium saline. The electrically stimulated release of hormone from isolated CC was abolished by the α‐adrenergic blocking agent, phenoxybenzamine, but potentiated by the ß‐adrenergic blocking agent, propranolol. Phenoxybenzamine did not interfere with release induced by high‐potassium saline. It is suggested that the postsynaptic receptors on the glandular cells are similar to the β‐adrenergic receptors of vertebrates. Octopamine was found to be present in the glandular lobe of the CC at concentrations of 0.62 pmole per gland pair. Reserpine depleted the content to 0.3 pmole per pair. Bathing the CC in 10−7Moctopamine resulted in the release of hyperlipemic hormone, and this release was blocked by phenoxybenzamine. It is concluded that the neurotransmitter involved in the synapse between axons of NCC II and the cells releasing hyperlipemic hormone is aminergic, possibly octopaminergic. Octopamine may well be a transmitter mediating hormone re

ISSN:0022-3034    

DOI:10.1002/neu.480120204

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

年代:1981

数据来源: WILEY

摘要:

AbstractColchicine and some other microtubule‐active agents inhibit the electrical responses of cockroach tibial spine mechanoreceptors. Lumicolchicine, a colchicine analog which does not bind to microtubule protein, does not inhibit mechanoreceptive responses. Colchicine inhibition of peripheral mechanoreceptive responses is fully reversible and dose dependent, but colchicine has no effect on conduction in leg nerve axons. Colchicine inhibition is therefore an effect on the sensory dendrites or soma. The inhibition produced by colchicine could be produced by several effects. Colchicine may inhibit because it (1) disrupts the numerous intracellular microtubules which are a part of this sensory receptor's dendrite, (2) blocks axoplasmic transport of essential materials to the sensory dendrite, or (3) binds to tubulin or other proteins in the dendritic membran

ISSN:0022-3034    

DOI:10.1002/neu.480120205

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

年代:1981

数据来源: WILEY

摘要:

AbstractN‐acetyltransferase activity in the pineal glands of immature rats (12‐14 days old) shows a spontaneous rise and fall when the glands are placed in organ culture. The peak of the 28‐fold change occurs 5–16 hr after the cultures are initiated. This observation can be interpreted in two ways: (1) the pup pineal gland is responding to norepinephrine released when nerve endings degenerate in culture, or (2) the pup pineal gland has an innate ability which is responsible. Whatever the mechanism, the phenomenon is associated with the development of pineal gland function since pineal glands of adult rats do not show a spontaneous rise and fall in identical expe

ISSN:0022-3034    

DOI:10.1002/neu.480120206

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

年代:1981

数据来源: WILEY

摘要:

AbstractA single neuronal cell biological assay for NGF has been used to quantitate factors in soluble extract of chick embryo that promote neurite outgrowth. The neurite growth promoting activity is detected as early as day 1.5 of embryonic life. Specific activity increases to maximum over the first four days and then decreases from day 5 to 6 during a growth spurt of the embryo. The tissue distribution of neurite growth promoting activity at eight embryonic days shows higher specific activity in peripheral structures that are richly innervated. Extract from all embryonic stages and from all tissues studied induces neurite outgrowth that is inhibited only partially by antibody to mouse NGF. Furthermore, the kinetics of neurite outgrowth and the neuronal populations responsive to extract differ from that of NGF. These observations indicate heterogeneity of the neurite growth promoting factors in soluble extracts of embryonic chick and demonstrate the presence of these factors before the responsive neurons leave the cell cycle and begin their differentiation processes.

ISSN:0022-3034    

DOI:10.1002/neu.480120207

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.480120208

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.480120209

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.480120210

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.480120201

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

年代:1981

数据来源: WILEY