ISSN:0022-3034    

DOI:10.1002/neu.480190102

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

年代:1988

数据来源: WILEY

摘要:

AbstractIt is becoming increasingly clear that the neuropeptide cholecystokinin (CCK), widely distributed in the rat hypothalamus and limbic system, is subject to both organizational and activational influences of steroid hormones. Sex differences in numbers of CCK‐immunoreactive elements have been demonstrated in sexually dimorphic structures such as the bed nucleus of the stria terminalis, medial preoptic nucleus, and ventromedial nucleus of the hypothalamus. Steroid activation of CCK has been indicated by findings that hypothalamic CCK levels and binding capacity vary over the estrous cycle. These studies, in combination with evidence of CCK mediation of sexually differentiated functions, prompted us to test for estrogen concentration among CCK‐containing cells of the female rat hypothalamus by combining the techniques of immunohistochemistry and autoradiography.A method employing 2‐week ovariectomies and perfusion fixation with 4% paraformaldehyde was compatible with the localization of both estrogen‐accumulating and CCK‐immunoreactive cell bodies. The maintenance of numbers of CCK‐positive cells after gonadectomy suggested that expression of this peptide may not be directly regulated by ovarian steroids in female rats. This suggestion was substantiated by the finding that, with rare exceptions, CCK‐immunoreactive cells did not concentrate estrogen in tissues collected from the anterior‐posterior extent of the bed nucleus of the stria terminalis, medial preoptic nucleus, anterior hypothalamic area, and paravent

ISSN:0022-3034    

DOI:10.1002/neu.480190103

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

年代:1988

数据来源: WILEY

摘要:

AbstractIn adult crickets,Teleogryllus oceanicus, unilateral auditory deafferentation causes the medial dendrites of an afferent‐deprived, identified auditory interneuron (Int‐1) in the prothoracic ganglion to sprout and form new functional connections in the contralateral auditory neuropil. The establishment of these new functional connections by the deafferented Int‐1, however, does not appear to affect the physiological responses of Int‐1's homolog on the intact side of the prothoracic ganglion which also innervates this auditory neuropil. Thus it appears that the sprouting dendrites of the deafferented Int‐1 are notfunctionallycompeting with those of the intact Int‐1 for synaptic connections in the remaining auditory neuropil following unilateral deaferentation in adult crickets. Moreover, we demonstrate that auditory function is restored to the afferent‐deprived Int‐1 within 4–6 days following deafferentation, when few branches of Int‐1's medial dendrites can be seen to have spouted. The strength of the physiological responses and extent of dendritic sprouting in the deafferented Int‐1 progressively increase with time following deafferentation. By 28 days following deafferentation, most of the normal physiological responses of Int‐1 to auditory stimuli have been restored in the deafferented Int‐1, and the medial dendrites of the deafferented Int‐1 have clearly sprouted and grown across into the contralateral auditory afferent field. The strength of the physiological responses of the deafferented Int‐1 to auditory stimuli and extent of dendritic sprouting in the deafferented Int‐1 are greater in crickets deafferented as juveniles than as adults. Thus, neuronal plasticity persists in Int‐1 following sensory deprivation from the earliest

ISSN:0022-3034    

DOI:10.1002/neu.480190104

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

年代:1988

数据来源: WILEY

摘要:

AbstractThe buccal ganglia of the marine molluscTritoniacontrol a variety of movements associated with feeding, including gut motility. The buccal ganglia and gut contain a class of peptides termed small cardioactive peptides (SCPs). Cobalt backfilling of the nerve which innervates the gut stains several buccal neurons including two pairs of reidentifiable cells, B11 and B12. Both appear white under epiillumination, a characteristic of peptidergic neurons in gastropods. Enzymatic and biochemical analyses of extracts from microdissected B11 cell bodies demonstrate that this neuron contains two species of SCPs. Labeling in organ culture followed by dissection and extraction of cell bodies indicates that these peptides were synthesized in B11. One of these peptides appears to be identical to SCPB, one of two SCPs that have been sequenced. The other SCP present in these neurons is novel. Less extensive analyses of extracts of B12 somata suggest that it also contains the same SCPs. In addition to the peptides, B11 also contains large quantities of acetylcholine (ACh) as determined by a radioenzymatic assay of cell body extracts. B12 does not contain measureable ACh. The concentration of the two peptides and ACh in the B11 cytoplasm is approximately 1 mM. Neuron B11 appears to be an appropriate model system for studying the biochemical and physiological properties of multiple transmitter neurons.

ISSN:0022-3034    

DOI:10.1002/neu.480190105

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

年代:1988

数据来源: WILEY

摘要:

AbstractTwo large multiple transmitter neurons are located in each buccal ganglion ofTritonia. One of these neurons (B11) contains large quantities of two neuropeptides and acetylcholine (ACh), whereas the other neuron (B12) appears to contain the same two peptides but no ACh. One of the peptides present in these neurons has recently been sequenced and is termed small cardioactive peptide B (SCPB). Both neurons regulate the motility of the gut. Stimulation of B11 produces a posteriorly directed peristalsis after a short latency. This gut movement may normally accompany swallowing. B11 stimulation also produces an increase in the rate of endogenous contractile activity that is similar to that produced by superfusion of the gut with low concentrations (10−8M) of SCPB. Stimulation of B12 produces a vigorous longitudinal contraction of the gut, initiated in the posterior part of the gut and not peristaltic in nature. This movement appears incompatible with swallowing behavior and may be involved in regurgitatio

ISSN:0022-3034    

DOI:10.1002/neu.480190106

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

年代:1988

数据来源: WILEY

摘要:

AbstractFeeding behavior in the gastropod molluscTritonia diomedeais controlled by a central pattern generator (CPG) in the buccal ganglia. The medially located, large dorsal white cells (B11) have been shown to contain two small cardioactive peptides (SCPs). A smaller nearby neuron (B12) also appears to contain the SCPs. B11's have also been shown to contain acetycholine (ACh), whereas B12's do not.We have shown earlier that intracellular stimulation of B11's drives contractions of the foregut. Here we show that intracellular electrical stimulation of B11's also elicits excitation of neurons B5 and stimulates the patterned motor output of the CPG. We showed earlier that B12's also stimulate contractions in the foregut, but they are in the opposite direction from those elicited by B11. We show here that electrical stimulation of B12's inhibits the output of the CPG.We showed earlier that superfusion of the isolated gut with SCPBenhances peristalsis, and here we report that superfusion of the buccal ganglion with SCPBelicits enhanced coordinated motor output from the CPG. The peptide has two effects on the bursting output of motor neurons. It produces an increase in (1) the rate of bursting and (2) the spike frequency during each burst. On the other hand, we reported earlier that ACh applied directly to isolated foregut inhibits ongoing peristalsis. Here we demonstrate that ACh superfusion of the buccal ganglion also inhibits the CPG output.Our evidence supports the view that in addition to stimulating foregut contractility, B11's modulate the output of the swallowing CPG by releasing a peptide from central terminals. We suggest roles for B11, B12, the SCPs, and ACh in controlling both central and peripheral aspects of feeding behavior.

ISSN:0022-3034    

DOI:10.1002/neu.480190107

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

年代:1988

数据来源: WILEY

摘要:

AbstractSmall cardioactive peptide B (SCPB) has an excitatory effect on both buccal neurons and musculature in numerous molluscan species. The present study reports the effects of SCPBon the activity of specified buccal neurons and the expression of the feeding motor program of the terrestrial slug,Limax maximums. Superfusion of an isolated CNS preparation with 10−6MSCPBresults in a 3–4‐fold increase in the burst frequency of the fast salivary burster neuron (FSB), while having no effect on the activity of another endogenous burster, the bilateral salivary neuron (BSN). The response of the FSB to SCPBiS dose dependent, with a threshold concentration of 2 × 10−8M. The response of the FSB to SCPBshowed no indication of desensitization, even after long‐term exposure (20 min).The feeding motor program (FMP) inLimaxis a discrete pattern of cyclical motor activity that can be initiated by lip nerve stimulation. In the presence of SCPBa previously subthreshold stimulus can initiate the full FMP. The pattern of the FMP, once initiated, appears unaffected by SCPB. Thus it is the responsiveness of the initiation process that is enhanced by SCPB. Histochemical studies revealed a number of buccal neuron somata and fibers that stain for SCPB‐like immunoreactive mat

ISSN:0022-3034    

DOI:10.1002/neu.480190108

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

年代:1988

数据来源: WILEY

ISSN:0022-3034    

DOI:10.1002/neu.480190101

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

年代:1988

数据来源: WILEY