Peptide YY (3-36) inhibits dopamine and norepinephrine release in the hypothalamus

Peptide YY (1-36) and peptide YY (3-36) are gut-derived hormones which are involved in feeding control in the hypothalamus. The hypothalamic mechanisms of feeding have been shown to be modulated by aminergic neurotransmitters, which could mediate the anorectic or orexigenic effects of neuropeptides and hormones. We have investigated the role of peptide YY (1-36) and peptide YY (3-36) on dopamine, norepinephrine, and serotonin release from hypothalamic synaptosomes in vitro. We found that peptide YY (3-36) inhibited depolarization-induced dopamine and norepinephrine release, leaving unaffected serotonin release, while peptide YY (1-36) did not modify either basal or stimulated amine release. We can hypothesize that the effects of peptide YY (3-36) could be mediated by inhibited hypothalamic dopamine and norepinephrine release, which could partially account for the anorectic activity of the peptide. On the other hand, peptide YY (1-36), which has a feeding stimulatory role, does not affect aminergic neurotransmission in the hypothalamus.