Functional significance of neural projections from the hypothalamic dorsomedial nucleus (DMN) to the paraventricular nucleus (PVN) was investigated using surgical lesion of the central part of the DMN. Under basal conditions, DMN lesion resulted in a decrease in magnocellular vasopressin (AVP) mRNA levels in the PVN, rise in pituitary proopiomelancortin (POMC) mRNA concentrations and elevated p...

The term 'learned helplessness' refers to a constellation of behavioral changes that follow exposure to stressors that are not controllable by means of behavioral responses, but that fail to occur if the stressor is controllable. This paper discusses the nature of learned helplessness, as well as the role of the dorsal raphe nucleus, serotonin, and corticotropin-releasing hormone in mediating t...

Individual effects of corticotropin-releasing hormone (CRH) and glucocorticoids on sleep have been difficult to discern due to the feedback effects each hormone exerts on the other. In addition, it is not known whether hypothalamic-pituitary-adrenal axis hormones alter sleep homeostasis or circadian influences on sleep propensity. We therefore analyzed sleep architecture and electroencephalogra...

There is growing evidence that stressors occurring during pregnancy can impair biological and behavioral responses to stress in the adult offspring. For instance, prenatal stress enhances emotional reactivity, anxiety, and depressive-like behaviors associated with a prolonged stress-induced corticosterone secretion and a reduction in hippocampal corticosteroid receptors. Among the neurotransmit...

Heterogeneity in homotypic cellular responses is an important feature of many biological systems, and it has been shown to be prominent in most anterior pituitary hormonal cell types. In this study, we analyze heterogeneity in the responses to hypothalamic secretagogues in the corticotroph cell population of adult male rats. Using the genetically encoded calcium indicator GCaMP6s, we determined...

Interactions between serotonin and corticotropin-releasing factor (CRF) have been demonstrated by various studies in different parts of the brain. Both are activated by stressful stimuli. Additionally, serotoninergic fibres directly synapse with the parvocellular division of the paraventricular nucleus (PVN) that mainly synthesize CRF. The functional impact of this serotonin-CRF interaction on ...

The possibility that habitual voluntary running induces a chronic change in adrenal glucocorticoid synthesis and secretion was examined in freely running mature female hamsters, in whom this behavior accelerates growth, reduces body fat levels, and elevates core temperature. Hamsters were free to run on horizontal discs or in vertical wheels between 32 and 80 days, in 14L:10D or in 10L:14D phot...

We showed previously that brief footshock stress and priming injections of heroin reinstate heroin-seeking after prolonged drug-free periods. Here, we examined whether the adrenal hormone, corticosterone, and brain corticotropin-releasing factor (CRF) were involved in such reinstatement. We tested the effects of adrenalectomy, chronic exposure to the corticosterone synthesis inhibitor metyrapon...