Question

Ghrelin's action on NPY/AgRP and POMC cells:

A) Ghrelin activates NPY/AgRP cells directly and inhibits POMC cells via the release of GABA

B) Ghrelin inhibits NPY/AgRP cells directly, but has no effect on POMC cells

C) Ghrelin receptors are only present on POMC cells

Answer 1

Ghrelin activates NPY/AgRP neurons to increase hunger and inhibits POMC neurons through GABA release, promoting food intake and reducing metabolism.

Step-by-step explanation:

The student has asked about the effects of ghrelin on two populations of neurons found in the hypothalamus: NPY/AgRP and POMC cells. The correct answer is A) Ghrelin activates NPY/AgRP cells directly and inhibits POMC cells via the release of GABA. Ghrelin, often referred to as the "hunger hormone", signals when you are hungry by activating NPY/AgRP neurons, which promote appetite and reduce metabolic rate. It also inhibits POMC neurons, which normally suppress food intake, thus further contributing to the feeling of hunger. This inhibition is achieved through the indirect pathway of GABA release, which is a neuroinhibitory transmitter that hinders the activity of POMC cells.