Medial versus lateral parabrachial nucleus lesions in the rat: effects on cholecystokinin- and D-fenfluramine-induced anorexia.
The two major components of the pontine parabrachial nucleus (PBN), the medial (gustatory) and lateral (visceral) subdivisions, have been implicated in a variety of ingestive behaviors. The present study examined the influence of bilateral ibotenic acid lesions of the medial or lateral PBN on the anorectic effects of two systemically administered drug treatments. In Experiment 1, 24-h food-deprived rats where injected with sulfated cholecystokinin (26-33) (CCK; 0, 4.0, or 8.0 microg/kg) and then given 60 min access to food. In Experiment 2, the influence of D-fenfluramine (DFEN; 0, 0.5, 1.0, or 2.0 mg/kg) on deprivation-induced feeding was examined in the same rats using the same behavioral procedure as in Experiment 1. Lesions of the lateral PBN abolished CCK-, but not DFEN-induced anorexia whereas lesions of the medial PBN augmented DFEN-, but had no influence on CCK-induced anorexia. The results suggest that the satiating effects of CCK and DFEN are mediated through different mechanisms involving, respectively, visceral and orosensory processing.
Department of Psychology, The University of Illinois at Chicago, 60607, USA.
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R
Trifunovic
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S
Reilly
D000818:Animals; D000855:Anorexia / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D002766:Cholecystokinin / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects / Q000502:physiology; D018690:Excitatory Amino Acid Agonists; D005246:Feedback / Q000502:physiology; D005277:Fenfluramine / Q000494:pharmacology*; D005508:Food Deprivation / Q000502:physiology; D007051:Ibotenic Acid; D008297:Male; D011149:Pons / Q000473:pathology / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018490:Serotonin Agents / Q000494:pharmacology*; D013649:Taste / Q000502:physiology
D018690:Excitatory Amino Acid Agonists; D018490:Serotonin Agents; D007051:Ibotenic Acid; D005277:Fenfluramine; D002766:Cholecystokinin