Intracerebroventricular CART peptide reduces food intake and alters motor behavior at a hindbrain site

Peptides from cocaine- and amphetamine-regulated transcript (CART) reduce f ood intake in rats when injected into the lateral ventricle. Hypothalamic a nd hindbrain sites important in the control of feeding contain CART-immunor eactive fibers. To further define the site of CART's anorectic action, we c ompared feeding and other behavioral responses to third or fourth ventricul ar (3V, 4V) CART-(55-102) in 6-h food-deprived rats, both before and after cerebral aqueduct occlusion. 3V CART reduced the volume of Ensure consumed and resulted in fewer observations of eating and grooming within the 30-min test session. These reductions were significantly attenuated by aqueduct o bstruction. 4V CART suppressed Ensure intake and resulted in decreased obse rvations of feeding both with and without aqueduct blockade. 3V CART produc ed flat-backed postures and movement-associated tremors that were prevented by aqueduct obstruction. 4V CART also produced these signs, both with and without aqueduct blockade. We conclude that the major hypophagic effect of intracerebroventricular CART is mediated at a hindbrain site. The associati on of CART- induced feeding suppression with altered motor behavior questio ns the specificity of intracerebroventricular CART for actions on feeding.