ANAT 322 Lecture Notes - Lecture 29: Vagus Nerve, Nucleus Accumbens, Anti-Obesity Medication

• School: McGill University
• Department: Anatomy & Cell Biology
• Course: ANAT 322
• Professor: David Ragsdale

Document Summary

Homeostatic system activated upon depletion of energy stores hypothalamus & brainstem. Hedonic system controlled by pleasure ventral tegmental area. Ko leptin/pomc gene massive obesity; any gene in pathway is essential. Ko npy/agrp no change in body weight; weird! Dtr under agrp promoter express dtr on nyp/agrp neurons. Agrp in brain only expressed small portion of arcuate nucleus in brain. Inject dt (ablate npy/agrp neurons) in mice w/dtr stopped eating. Dt on 1-day-old mice had no effect even though agrp neurons ablated. Brain more plastic when younger, compensatory adaption to missing nyp/agrp neurons. Dt on adult mice stop eating, starved. Something else in npy/agrp neurons essential to feeding behaviour. Treat w/dt & gaba receptor agonist restored body weight & food intake. Csf flows in one direction; 3rd ventricle goes to 4th ventricle, doesn"t go back. Inject gaga receptor agonist in 3rd ventricle or 4th ventricle. Injection in 4th ventricle most efficient at normalizing body weight (than 3rd ventricle) - brainstem.