Cortical [3H]ketanserin binding and 5-HT2A receptor-mediated behavioral responses in obese Zucker rats.
Past studies have indicated that genetically obese Zucker (fa/fa) rats are hypercorticoid, and that this neuroendocrine alteration plays a key role in the syndrome. In keeping with the proposal that glucocorticoids may upregulate central 5-HT2A receptors, we have studied the effects of acute and repeated 5-HT2A receptor stimulation by 1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane (DOI) in lean and obese Zucker rats. Acute injection of DOI (2 mg/kg, SC) elicited a lower number of head shakes in obese rats compared to that measured in lean rats. Conversely, neither DOI-elicited decreases in food intakes and body weights nor cortical [3H]ketanserin binding were affected by obesity. In rats repeatedly pretreated with DOI, biochemical and functional indices of 5-HT2A receptor downregulation failed to reveal an effect of obesity. It is suggested that 5-HT2A receptor-mediated functions, but not their downregulation, may be differentially affected in the hypercorticoid obese Zucker rat.
Chaouloff
F
F
Laboratoire de Pharmacologie, CNRS, CHUNecker, Paris, France.
Coupry
I
I
Baudrie
V
V
D000662:Amphetamines / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D004435:Eating / Q000187:drug effects; D007650:Ketanserin / Q000378:metabolism*; D008297:Male; D009765:Obesity / Q000523:psychology*; D051381:Rats; D011924:Rats, Zucker; D011985:Receptors, Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology
D000662:Amphetamines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D007650:Ketanserin; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine