Evidence shows that neuropeptide Y (NPY) neurons are involved in mediating the anorexigenic action of leptin via neuronal circuits in the hypothalamus. However, studies have produced limited data on the cellular processes involved and whether hypothalamic NPY neurons are susceptible to cellular leptin resistance. To investigate the direct regulation of NPY secretion by leptin, we used novel NPY...

Considering the coexistence of neuropeptide Y (NPY) and norepinephrine in perivascular sympathetic nerves and the known vasoconstrictor cooperation of NPY with norepinephrine, we investigated the involvement of NPY in long-term control of cardiovascular functions using NPY transgenic (NPY-tg) rats. These rats were developed by injection of the rat (Sprague-Dawley) pronuclei with a 14.5-kb clone...

Neuropeptide Y (NPY) has been implicated in the phase shifting of circadian rhythms in the hypothalamic suprachiasmatic nucleus (SCN). Using long-term, multiple-neuron recordings, we examined the direct effects and phase-shifting properties of NPY application in rat SCN slices in vitro (n = 453). Application of NPY and peptide YY to SCN slices at circadian time (CT) 7.5-8.5 produced concentrati...

Previously, in vivo studies showed that neuropeptide Y (NPY) elevates vascular permeability in isolated lung perfusion preparations, possibly through binding to the NPY Y(3) receptor. The present study used monolayers in a double-chamber culture method under conditions of normoxia (5% CO(2)-20% O(2)-75% N(2)) or hypoxia (5% CO(2)-5% O(2)-90% N(2)) to test the hypothesis that NPY directly affect...

Neurons that release neuropeptide Y (NPY) have important effects on hypothalamic homeostatic regulation, including energy homeostasis, and innervate hypocretin neurons. Using whole-cell patch-clamp recording, we explored NPY actions on hypocretin cells identified by selective green fluorescent protein expression in mouse hypothalamic slices. NPY reduced spike frequency and hyperpolarized the me...

Neuropeptide Y (NPY) neurons in both the arcuate nucleus of the hypothalamus (ARH) and the dorsomedial hypothalamus (DMH) have been implicated in food intake and obesity. However, while ARH NPY is highly expressed in the lean animal, DMH NPY mRNA expression is observed only after diet-induced obesity (DIO). Furthermore, while ARH NPY neurons are inhibited by leptin, the effect of this adipokine...

Neuropeptide Y (NPY) is released from an extensive network of postganglionic sympathetic perivascular neurons. NPY has been shown to affect vascular tone postsynaptically by 1) directly stimulating contraction; 2) inhibiting vasorelaxation; and 3) potentiating contraction elicited by exogenous vasoconstrictors. The molecular mechanisms mediating these effects of NPY are undefined. Therefore, we...

Effects of neuropeptide Y (NPY) on motility of the proximal stomach was examined in anesthetized rats. Intragastric pressure was measured using a balloon situated in the proximal part of the stomach. Administration of NPY into the fourth ventricle induced relaxation of the proximal stomach in a dose-dependent manner. Administration of an Y1 receptor (Y1R) agonist [Leu31, Pro34]NPY induced a lar...

Exposure of chicks to a high ambient temperature (HT) has previously been shown to increase neuropeptide Y (NPY) mRNA expression in the brain. Furthermore, it was found that NPY has anti-stress functions in heat-exposed fasted chicks. The aim of the study was to reveal the role of central administration of NPY on thermotolerance ability and the induction of heat-shock protein (HSP) and NPY sub-...

Neuropeptide Y (NPY) plays a key role in both food intake and GnRH secretion. Food deprivation elevates hypothalamic NPY activity and suppresses LH and gonadal steroid secretion. Similarly, lactation up-regulates NPY expression as food consumption increases and estrous cycles cease. These observations suggest that NPY coordinates reproductive suppression in response to energy deficiency; if so,...