We investigated the effects of various serotonergic drugs and serotonin (5-HT) depletion on lipopolysccharide (LPS)-induced anorexia in Sprague-Dawley male rats. For serotonin depletion, we injected P-chlorophenylalanine (PCPA), inhibitor of serotonin synthesis, into intraperitoneum (i.p) of rats. While LPS injected (500 μg/kg BW) rats almost had no food intake for 24 hours, PCPA pretreatment (300 mg/kg BW) for 4 days before LPS injection significantly increased food intake (p<0.05). Although 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), 5-HT(1A) receptor agonist, had no effect on normal food intake, pretreatment of 8-OH-DPAT (1mg/kg BW, subcutanious) 30 minutes before LPS injection increased food intake for 24 hours by 266% compared with non-treated group (p<0.005). However food intake of 8-OH-DPAT pretreated rats did not reach control level. Metergolin (5 mg/kg BW, i.p), 5-HT1 and 5-HT2 receptors antagonists, also had no effect on normal food intake, but significantly increased food intake for 4 hours after LPS injection. Injection of Mianserin (5-HT2 receptor antagonist, 5 mg/kg, i.p.) did not effect on food intake of either normal rats or LPS injected rats. In conclusion, pretreatment of PCPA, 8-OH-DPAT, and metergolin partially inhibited anorexia induced by LPS injection in rats.
Source: Korean J Physiol Pharmacol.2001 Dec;5(Suppl II):S99
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