Infusion of the 5-hydroxytryptamine agonists RU24969 and TFMPP into the paraventricular nucleus of the hypothalamus causes hypophagia.
The 5-HT1B agonist RU24969 when given either systemically (1 mg/kg SC) or by infusion (0.5, 1.0, 2.0 micrograms) into the region of the paraventricular nucleus of the hypothalamus caused dose-dependent hypophagia in rats previously deprived of food for 18 h. Similar results were obtained at the above dosages of 1-[3-(trifluoromethyl) phenyl] piperazine (TFMPP), which acts on 5-HT1B and possibly also on 5-HT1C receptors. Neither drug significantly affected locomotion following central administration. Food intake was significantly decreased when the 5-HT1A agonist 8-OH-DPAT was given systemically (1 mg/kg SC) to rats previously deprived of food but was unaffected when 8-OH-DPAT (1 microgram) was infused into the paraventricular nucleus of both food-deprived and free feeding rats. Therefore, hypophagia occurs when hypothalamic 5-HT1B (and possibly 5-HT1C) but not 5-HT1A receptors are activated.
Hutson
P H
PH
Department of Neurochemistry, Institute of Neurology, London, UK.
Donohoe
T P
TP
Curzon
G
G
D000818:Animals; D005247:Feeding Behavior / Q000187:drug effects*; D007211:Indoles / Q000008:administration & dosage / Q000494:pharmacology*; D007267:Injections; D007279:Injections, Subcutaneous; D008297:Male; D010879:Piperazines / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D014697:Ventromedial Hypothalamic Nucleus / Q000033:anatomy & histology
D007211:Indoles; D010879:Piperazines; C018406:1-(3-trifluoromethylphenyl)piperazine; C025145:5-methoxy 3-(1,2,3,6-tetrahydro-4-pyridinyl)1H indole