Effects of monoamine receptor antagonists on nicotine-induced hypophagia in the rat

• Published in: European journal of pharmacology 1997-02, Vol.321 (2), p.157-162
• Main Authors: Zarrindast, Mohammad-Reza, Oveisi, Mohammad-Reza
• Format: Article
• Language: English
• Subjects: 5-HT receptor antagonist; Acetylcholine receptor antagonist; Adrenergic Antagonists - pharmacology; Adrenoceptor antagonist; Animals; Anorexia; Anorexia - chemically induced; Atropine - pharmacology; Biological and medical sciences; Cholinergic Agents; Cholinergic Antagonists - pharmacology; Cholinergic system; Dopamine Antagonists - pharmacology; Dopamine receptor agonist; Eating - drug effects; Hexamethonium - pharmacology; Male; Mecamylamine - pharmacology; Medical sciences; Muscarinic Antagonists - pharmacology; Neuropharmacology; Neurotransmitters. Neurotransmission. Receptors; Nicotine; Nicotine - pharmacology; Nicotinic Antagonists - pharmacology; Pharmacology. Drug treatments; Rat; Rats; Rats, Wistar; Receptors, Neurotransmitter - antagonists & inhibitors; Serotonin Antagonists - pharmacology; Tobacco, tobacco smoking; Toxicology
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/S0014-2999(96)00935-1

(−)-Nicotine, in doses of 0.2–0.6 mg/kg intraperitoneally (i.p.), induced a dose-dependent anorexia 1 h, 2 h and 4 h after food presentation in 20-h food-restricted male rats. The anorectic response of nicotine (0.4 mg/kg, 30 min before the test) was prevented by pretreatment with the central nicotine receptor antagonist mecamylamine (0.5 and 1 mg/kg). The peripheral nicotine receptor antagonist hexamethonium (5 and 10 mg/kg), the muscarinic receptor antagonist atropine (5 and 10 mg/kg), the dopamine D 2 receptor antagonist pimozide (0.5 and 1 mg/kg), the dopamine D 1 receptor antagonist SCH23390 ( R-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1 H-3-benzazepine-7ol maleate; 0.05 and 0.1 mg/kg), the α-adrenoceptor antagonist phenoxybenzamine (5 and 10 mg/kg), and the β-adrenoceptor antagonist propranolol (5 and 10 mg/kg) amplified the nicotine response while promoting anorexia by themselves. The dopamine D 2 receptor antagonist sulpiride (25, 50 and 100 mg/kg) increased food intake and amplified the anorectic effect of nicotine. The 5-HT receptor antagonists metergoline (0.5 and 1 mg/kg) and mianserin (1 and 2 mg/kg) increased the nicotine effect. When the antagonists were used alone, metergoline did not change food intake, while mianserin increased food intake. It can be concluded that part of nicotine-induced anorexia is mediated through central nicotinic receptors.