Intracerebroventricular CART peptide reduces rat ingestive behavior and alters licking microstructure.
Intracerebroventricular administration of cocaine- and amphetamine-regulated transcript (CART) peptides reduces food intake and increases c-Fos in brain areas involved in the control of feeding. To discern behavioral mechanisms through which CART alters the microstructure of feeding, we injected CART-(55--102) (0.1, 0.5, 1, 2 microg, and saline controls) into the lateral ventricle of male Sprague-Dawley rats 5 min before dark onset and, using lickometers, monitored the ingestion of an Ensure liquid diet for the first 6 h of dark. At a threshold dose of 1 microg, CART dose dependently 1) decreased intake of Ensure in licks; 2) decreased meal size, but did not alter meal duration or number; 3) reduced initial lick rate of meals; and 4) significantly reduced burst number, licks/burst, and licks/cluster. CART dose dependently increased interlick interval (0.5 microg threshold, 192 +/- 4 vs. 183 +/- 3 ms, control; 1 microg: 201 +/- 1 ms; 2 microg: 214 +/- 6 ms). These data suggest that altered oral motor function, and possibly palatability perception, may be fundamental to the anorexigenic action of CART.
Aja
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S
Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. susanaja@hotmail.com
Schwartz
G J
GJ
Kuhar
M J
MJ
Moran
T H
TH
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005247:Feeding Behavior / Q000187:drug effects*; D007276:Injections, Intraventricular; D008297:Male; D009419:Nerve Tissue Proteins / Q000008:administration & dosage* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014059:Tongue / Q000187:drug effects* / Q000502:physiology*; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
D009419:Nerve Tissue Proteins; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein