Abstract
Oxytocin neurons have a physiological role in food intake and energy balance. Central administration of oxytocin is powerfully anorexigenic, reducing food intake and meal duration. The central mechanisms underlying this effect of oxytocin have become better understood in the past few years. Parvocellular neurons of the paraventricular nucleus project to the caudal brainstem to regulate feeding via autonomic functions including the gastrointestinal vago-vagal reflex. In contrast, magnocellular neurons of the supraoptic and paraventricular nuclei release oxytocin from their dendrites to diffuse to distant hypothalamic targets involved in satiety. The ventromedial hypothalamus, for example, expresses a high density of oxytocin receptors but does not contain detectable oxytocin nerve fibers. Magnocellular neurons represent targets for the anorexigenic neuropeptide α-melanocyte stimulating hormone. In addition to homeostatic control, oxytocin may also have a role in reward-related feeding. Evidence suggests that oxytocin can selectively suppress sugar intake and that it may have a role in limiting the intake of palatable food by inhibiting the reward pathway.
Highlights
Unlike Roald Dahl’s “enormously fat” Augustus Gloop – a boy who pursued eating as a hobby – humans usually eat much less than they could
Oxytocin receptors in the ventromedial nucleus of the hypothalamus (VMN) have an established role in sexual behavior in female rats (McCarthy et al, 1994), and we have previously suggested that they are involved in the reciprocal regulation of appetite and sexual behavior (Leng and Ludwig, 2008)
It seems clear that oxytocin has a physiological role in energy balance through its actions in the caudal brainstem, but probably through actions within the hypothalamus, including at the VMN, and possibly at other sites in the brain
Summary
Unlike Roald Dahl’s “enormously fat” Augustus Gloop – a boy who pursued eating as a hobby – humans usually eat much less than they could. In the 1990s, several studies reported anorexigenic effects of central oxytocin: low doses of oxytocin given icv dose-dependently inhibited food intake in rats, increased the latency to begin feeding and reduced meal duration in both hungry and satiated animals, and these actions could be blocked by oxytocin receptor antagonists (Arletti et al, 1990; Olson et al, 1991a).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
