Darkthorn’s Blog

- The hypothalamus generates homeostatic and behavioural responses to ‘interoreceptive’ stimuli

- humeral, secretion of hormones

- visceromotor, changes in the nervous system

- somatic motor, behavioral responses

- long term control of energy balance

- dual center model for regulation of feeding

- Frohlich’s syndrome – injury to the pituitary gland (WRONG!)

- role of the hypothalamus (Hetherington and Ranson)

- lesions of lateral hypothalamus – thin mouse

- lesions of anteromedial hypothalamus – fat mouse

- lipostatic theory

- the brain monitors the amount of body fat and defends this against change

- ob gene, expressed in fat cells

- db receptor, produced in brain

- leptin is produced in the fat cells and received in the brain

- decreased levels of leptin in starvation

- NPY/AgRP neurons of articulate nucleus – stimulate feeding behavior and inhibit secretion of hormones controlling ACTH & TSH

- increased levels of leptin in weight gain

- inhibit feeding behavior (MSH/CART neurons)

- stimulate release of ACTH and thyrrotropin

- NPY + AgRP – ‘oxexigenic’

- POMC + CART – ‘anorexigenic’

- Short term control of energy balance

- Ghrelin produced in stomach acts on feeding centers (NPY and AgRP), building up prior to a meal and then reduced following the meal

- Satiety signals – gastric distention and cholecystekinin and insulin

- Hedonistic feeding excites dopaminergic neurons