The anorectic effect of the selective dopamine D1-receptor agonist A-77636 determined by meal pattern analysis in free-feeding rats.
Free-feeding rats meet much of their daily energy requirements by consuming food in meals during the nocturnal phase of the night/day cycle. Meal pattern analysis methodology has been developed to record the patterns of meal taken over a 24-h period, and to provide detailed information on a number of meal-related parameters. Previous work indicates that selective dopamine D1-receptor agonists reduce food intake in short-term feeding tests under the control of homeostatic or hedonic factors. In the present study, our aim was to investigate the effects of the dopamine D1-receptor agonist, A-77636 (0.1-1.0 mg/kg, s.c.), administered just prior to the start of the night period, on the free-feeding and drinking patterns of rats maintained on a standard ad libitum diet. The results indicate that A-77636 exerted a suppressant effect on food intake, due principally to a reduction in meal size and duration. We conclude that there is a dopamine D1-receptor involvement in the normal controls of meal size, and that selective D1-receptor agonists may act to limit meal size.
School of Psychology, University of Liverpool, Eleanor Rathbone Building, Liverpool L69 7ZA, UK. s.j.cooper@liverpool.ac.uk
Steven J
SJ
Cooper
Hessah A
HA
Al-Naser
Peter G
PG
Clifton
D000218:Adamantane / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001067:Appetite Depressants / Q000494:pharmacology*; D001578:Benzopyrans / Q000494:pharmacology*; D002940:Circadian Rhythm; D018491:Dopamine Agonists / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects*; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D051381:Rats; D017447:Receptors, Dopamine D1 / Q000819:agonists*
D001067:Appetite Depressants; D001578:Benzopyrans; D018491:Dopamine Agonists; D017447:Receptors, Dopamine D1; C079415:A 77636; D000218:Adamantane