Oxytocin and appetite.

Oxytocin has potent central effects on feeding behaviour, as well as on social and sexual behaviours, and one likely substrate for its anorectic effect is the ventromedial nucleus of the hypothalamus. This nucleus expresses a high density of oxytocin receptors, but contains very few oxytocin-containing fibres, hence it is a likely target of 'neurohormonal' actions of oxytocin, including possibly oxytocin released from the dendrites of magnocellular oxytocin neurones. As oxytocin release from dendrites is regulated independent of electrical activity and of secretion from the neurohypophysis, exactly how this release is regulated by metabolic and reproduction-related signals remains to be established fully. Intriguingly though, it looks as though this central release of oxytocin from magnocellular neurons might be instrumental in a fundamental shift in motivational behaviour - switching behaviour from being driven by the need to find and consume food, to the need to reproduce.