基础医学神经生物学课件动机与成瘾.ppt

Motivation and Addiction;The long-term regulation of feeding behavior by motivation (1)Energy Balance (2)hormonal,hypothalamic regulation of body fat, feeding (3)body fat and food consumption (4)the hypothalamus and feeding (5)the effects of decreased leptin level on the hypothalamus (6) the effects of elevated leptin level on the hypothalamus (7)the control of feeding by lateral hypothalamic peptides;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;吴鎏桢;Remember that leptin levels rise when body fat is increased and they fall when body fat is decreased A rise in leptin levels increases α-MSH and CART in arcuate nucleus neurons. These anorectic peptides act on the brain to inhibit feeding behavior and increase metabolism. A fall in leptin levels increases NPY and AgRP in the arcuate nucleus and MCH and orexin in the lateral hypothalamic area. These orexigenic peptides act on the brain to stimulate feeding behavior and decrease metabolism. ;The short-term regulation of feeding behavior by motivation (1)gastric distension (2)cholecystokinin CCK (3)Insulin Other motivated behaviors (1)drinking (2)temperature regulation;吴鎏桢;Synergistic action of gastric distension and CCK on feeding behavior. Both signals converge onaxons in the vagus nerve that trigger satiety. ;;吴鎏桢;吴鎏桢;Chang in hypothalamic serotonin levels before and during a meal. The mood elevating effects of eating are believed to be related to the release of serotonin in the brain. (Soure: Adapted from Schwartz et al,1990) ;Pathways triggering volumetric thirst. Hypovolemia is detected in two ways, First, angiotensin II, released into the blood-stream in response to decreased blood flow to the kidneys, activates neurons in the subfornical organ. Second, mechanosensory axons in the vagus nerve, detecting a drop in blood pressure, activate neurons in the nucleus of the solitary tract, The subfornical organ and nucleus of the solitary tract relay this in formation to the hypothalamus, whi