Effects of ghrelin and amylin on dopamine, norepinephrine and serotonin release in the hypothalamus.

Ghrelin and amylin are gut-derived hormones that stimulate and inhibit food intake, respectively. Feeding is modulated by aminergic neurotransmitters in the hypothalamus. We have evaluated the effects of ghrelin and amylin on dopamine, norepinephrine and serotonin release from rat hypothalamic synaptosomes. We found that ghrelin did not modify dopamine or norepinephrine release, but inhibited serotonin release. On the other hand, amylin inhibited dopamine release, without affecting norepinephrine or serotonin. We conclude that the appetite-stimulating activity of ghrelin could be mediated by inhibited serotonin release, while the anorectic effects of amylin could involve inhibited release of dopamine in the hypothalamus.