In rodents, hypocretin (HCRT, also called orexin) influences a variety of endocrine, autonomic, and metabolic functions. The present study was undertaken to determine whether the HCRT-producing circuit is involved in the hypothalamic regulation of homeostasis in primates as well. We studied female monkeys (Cercopithecus aethiops) that were either fed or fasted for 24 h. Immunocytochemistry reve...

From the perspective of comparative morphology, the distribution of non-monoaminergic neurons in the common marmoset (Callithrix jacchus) was investigated using an immunohistochemical method with specific antibodies to tyrosine hydroxylase (TH) and aromatic-L-amino acid decarboxylase (AADC).TH-immunoreactive (IR) neurons (but not AADC-IR) neurons were observed in the olfactory tubercle, preopti...

Sleep is influenced by diverse factors such as circadian time, affective states, ambient temperature, pain, etc., but pathways mediating these influences are unknown. To identify pathways that may influence sleep, we examined afferents to the ventrolateral preoptic nucleus (VLPO), an area critically implicated in promoting sleep. Injections of the retrograde tracer cholera toxin B subunit (CTB)...

The hypothalamic neuropeptide melanin-concentrating hormone (MCH) increases feeding when injected intracerebroventricularly in rats. To identify the hypothalamic nuclei responsible for the orexigenic effect, we injected the peptide into discrete hypothalamic nuclei known to express the MCH receptor, MCH1R. MCH (0.6 nmol) elicited a rapid and significant increase in feeding in satiated rats foll...

Systemic inflammatory response syndrome is associated with either fever or hypothermia, but the mechanisms responsible for switching from one to the other are unknown. In experimental animals, systemic inflammation is often induced by bacterial lipopolysaccharide (LPS). To identify the diencephalic and brainstem structures involved in the fever-hypothermia switch, we studied the expression of c...

Previous studies suggest that sympathetic responses evoked from the preoptic area in anesthetized rats require activation of neurons in the dorsomedial hypothalamus. Disinhibition of neurons in the dorsomedial hypothalamus in conscious rats produces physiological and behavioral changes resembling those evoked by microinjection of muscimol, a GABA(A) receptor agonist and neuronal inhibitor, into...

The hypothalamus is a forebrain structure critically involved in the organization of defensive responses to aversive stimuli. Gamma-aminobutyric acid (GABA)ergic dysfunction in dorsomedial and posterior hypothalamic nuclei is implicated in the origin of panic-like defensive behavior, as well as in pain modulation. The present study was conducted to test the difference between these two hypothal...