Ventromedial nucleus

The ventromedial nucleus of the hypothalamus is involved in the regulation of feeding behaviour and glucose homeostasis ,ref>King BM (2006) The rise, fall, and resurrection of the ventromedial hypothalamus in the regulation of feeding behavior and body weight Physiol Behav 87:221-44, sexual behaviour and aggression.

Several appetite-inhibiting peptides have been detected in the VMN, including brain derived neurotrophic factor (BDNF) and pituitary adenylate cyclase-activating polypeptide (PACAP), and this region is directly affected by appetite-stimulating factors ghrelin and orexin-A, and by the appetite-inhibiting hormone leptin In recent years, research on the contribution of the VMN to energy homeostasis has focused on VMN neurones that express the transcription factor steroidogenic factor 1 (SF1), which is essential for its development In the mouse, the VMN is the only site of SF1 expression in the hypothalamus, and the knock out of SF1 in mice results in abnormal VMN development, and in late-onset obesity. Since this discovery, several reports have linked SF1 neurones with leptin signalling, with glucose homeostasis, and with the regulation of expression of cannabinoid receptor 1 (CBR1) and BDNF. The expression of SF1 delineates the dorsal and central regions of the VMN.

The VMN can be subdivided into dorsomedial, central, and ventrolateral regions based on the expression of transcription factors, receptors, and neuropeptides. . This nucleus is also electrophysiological heterogeneous, containing several subpopulations of cells that differ in their spontaneous discharge characteristics and in their responses to various stimuli. In the control of satiety, the VMN is a likely target for another appetite-inhibiting factor, the centrally-released peptide oxytocin. I.c.v. injection of oxytocin agonists potently inhibits food intake, and these effects are prevented by oxytocin antagonists. Within the brain, oxytocin is released from centrally-projecting parvocellular neurons of the paraventricular nucleus (PVN), and from the soma and dendrites of magnocellular neurons of the PVN and supraoptic nucleus. Both of these populations are activated during feeding, and by appetite-inhibitor peptide glucagon-like peptide 1 (GLP-1). The VMN is a site of exceptionally dense expression of oxytocin receptors. , particularly in the ventrolateral VMN. Oxytocin receptors in the VMN are involved in sexual behaviour in female rats where they are regulated by estrogen, as well as in appetite regulation.

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