Involvement of dynorphin and the kappa opioid receptor in feeding.

Dynorphin-(1-17) produces a highly specific increase in food ingestion. Similar enhancement of food ingestion is found with dynorphin fragments (1-10), (1-11), (1-13) and (3-13) but not with (1-8) and (1-9). Dynorphin B (rimorphin) also enhances food intake. The highly specific kappa agonist U-50,488 also enhances food intake as do a number of other kappa-opiate receptor agonists. These studies provided further for the role of a highly specific dynorphin-kappa opioid receptor in the modulation of feeding.