Mechanism of Action
Ghrelin has emerged as the first identified circulating hunger hormone. Ghrelin and synthetic ghrelin mimetics (the growth hormone secretagogues) increase food intake and increase fat mass by an action exerted at the level of the hypothalamus. They activate cells in the arcuate nucleus that include the orexigenic neuropeptide Y (NPY) neurons. Ghrelin-responsiveness of these neurons is both leptin- and insulin-sensitive. Ghrelin also activates the mesolimbic cholinergic-dopaminergic reward link, a circuit that communicates the hedonic and reinforcing aspects of natural rewards, such as food, as well as of addictive drugs, such as ethanol. Indeed, central ghrelin signalling is required for reward from alcohol. and palatable/rewarding foods. There is also strong evidence that ghrelin has a peripheral appetite modulatory effect on satiety by affecting the mechanosensitivity of gastric vagal afferents, making them less sensitive to distension resulting in over eating.
Read more about this topic: Ghrelin
Famous quotes containing the words mechanism of, mechanism and/or action:
“Life is an offensive, directed against the repetitious mechanism of the Universe.”
—Alfred North Whitehead (1861–1947)
“The two elements the traveler first captures in the big city are extrahuman architecture and furious rhythm. Geometry and anguish. At first glance, the rhythm may be confused with gaiety, but when you look more closely at the mechanism of social life and the painful slavery of both men and machines, you see that it is nothing but a kind of typical, empty anguish that makes even crime and gangs forgivable means of escape.”
—Federico García Lorca (1898–1936)
“Insurrection:... insurrection as soon as circumstances allow: insurrection, strenuous, ubiquitous: the insurrection of the masses: the holy war of the oppressed: the republic to make republicans: the people in action to initiate progress. Let the insurrection announce with its awful voice the decrees of God: let it clear and level the ground on which its own immortal structure shall be raised. Let it, like the Nile, flood all the country that it is destined to make fertile.”
—Giuseppe Mazzini (1805–1872)