Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Experiments were undertaken to investigate the effects of intracerebroventricular (i.c.v.) oxytocin (OT) on the response of supraoptic OT neurones to stimulation of the dorsomedial nucleus (DMH), in the suckled lactating rat. Under control conditions, the majority of OT neurones displayed either weak excitation to DMH stimulation, or no response. Following i.c.v. OT injection, all neurones showed a pronounced long-latency (70-115 ms) excitatory response, and the number of spikes evoked per stimulus pulse was significantly increased. This increased excitatory response was accompanied by facilitation of the milk-ejection reflex. Some OT neurones also displayed a short latency (8-13 ms) excitation to DMH stimulation, but this was unaffected by i.c.v. OT. In conclusion, the facilitation of bursting in OT neurones by i.c.v. OT is associated with potentiation of long-latency excitatory responses evoked by DMH stimulation.
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PMID:Central oxytocin potentiates excitatory responses of oxytocin neurones to stimulation of the dorsomedial hypothalamic nucleus in the suckled rat. 1175 Sep 93

It is widely accepted that leptin acts on first-order neurons in the arcuate nucleus (ARC) with information then relayed to other hypothalamic centers. However, the extent to which leptin mediates its central actions solely, or even primarily, via this route is unclear. We used a model of hypothalamo-pituitary disconnection (HPD) to determine whether leptin action on appetite-regulating systems requires the ARC. This surgical preparation eliminates the ARC. We measured effects of iv leptin to activate hypothalamic neurons (Fos labeling). In ARC-intact animals, leptin increased the percentage of Fos-positive melanocortin neurons and reduced percentages of Fos-positive neuropeptide Y neurons compared with saline-treated animals. HPD itself increased Fos labeling in the lateral hypothalamic area (LHA). Leptin influenced Fos labeling in the dorsomedial nucleus (DMH), ventromedial nucleus, and paraventricular nucleus (PVN) in HPD and normal animals, with effects on particular cell types varying. In the LHA and DMH, leptin decreased orexin cell activation in HPD and ARC-intact sheep. HPD abolished leptin-induced expression of Fos in melanin-concentrating hormone cells in the LHA and in CRH cells in the PVN. In contrast, HPD accentuated activation in oxytocin neurons. Our data from sheep with lesions encompassing the ARC do not suggest a primacy of action of leptin in this nucleus. We demonstrate that first order to second order signaling may not represent the predominant means by which leptin acts in the brain to generate integrated responses. We provide evidence that leptin exerts direct action on cells of the DMH, ventromedial nucleus, and PVN.
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PMID:The action of leptin on appetite-regulating cells in the ovine hypothalamus: demonstration of direct action in the absence of the arcuate nucleus. 2041 Feb 8