Download Feeding Pathways

Feeding Pathways
Hunger vs. Satiety
Controlled by communication between the gut and
parasympathetic nervous system
Neuroscience (Bears, Connors, Paradiso)
Some Basic Feeding Terminology
• Feeding Behavior:
– Hyperphagy: increase in food intake (often
used to explain pathological eating)
– Hypophagy: decrease in food intake
• Feeding Physiology:
– Orexigenic: release of a drug or hormone that
increases food intake
– Anorexigenic: release of a drug or hormone
that decrease food intake
Peripheral Regulation of Food
Intake
• Leptin (anorexigenic; satiety)
• Ghrelin (orexigenic; hunger)
Dysregulation of leptin leads to…
• The ob/ob mouse: do not have circulating
leptin levels, but this does not mean that
they are insensitive to leptin
– In fact, they are hypersensitized to
exogenously administered leptin. WHY?
• animal model of Type II diabetes
Central Regulation of Food Intake
The BIG THREE hypothalamic
areas regulating food intake are:
1) Lateral hypothalamus
2) Ventromedial hypothalamus
3) Arcuate Nucleus
Central Regulation of Hyperphagy
• NPY/AgRPcontaining
enhance feeding
behavior
Central Regulation of Hypophagy
• αMSH/CARTcontaining inhibit
feeding behavior
Balance Between Two Pathways
• Competitive
agonism of MSH
receptors and
antagonism of
MC4 receptors by
leptin
Central Regulation of Thirst
• Communication
between neurons in
the pituitary (organum
vasculosum of lamina
terminalis [OVLT] and
vasopressin-secreting
neurons) and kidneys
• Diabetes Insipidus