The blockade of H1 receptors attenuates the suppression of feeding and diuresis induced by inhibition of histamine catabolism

• Published in: Pharmacology, biochemistry and behavior Vol. 59; no. 3; pp. 753 - 758
• Main Authors: LECKLIN, A, TUOMISTO, L
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Science 01.03.1998
• Subjects: Animals; Biological and medical sciences; Brain Chemistry - drug effects; Diuresis - drug effects; Enzyme Inhibitors - pharmacology; Feeding Behavior - drug effects; General and cellular metabolism. Vitamins; Histamine - metabolism; Histamine Antagonists - pharmacology; Histamine H1 Antagonists - pharmacology; Histamine H2 Antagonists - pharmacology; Male; Medical sciences; Pharmacology. Drug treatments; Piperidines - pharmacology; Pyrilamine - pharmacology; Pyrimethamine - analogs & derivatives; Pyrimethamine - pharmacology; Ranitidine - pharmacology; Rats; Rats, Wistar; Water-Electrolyte Balance - drug effects; Diuresis; Feeding behavior; Rat; Enzyme; Transferases; Rodentia; Central nervous system; Enzyme inhibitor; Histamine; Vertebrata; Mammalia; Methyltransferases; Food intake; Histamine N-methyltransferase; Animal; Anorectic; Mechanism of action; H1 Histamine receptor; Brain (vertebrata)
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/S0091-3057(97)00465-6

Metoprine elevates brain histamine content by blocking the conversion of histamine to methylhistamine. It suppresses food intake, increases water intake. and induces diuresis in rats. In the present experiment, to study which receptors were involved in these metoprine-induced changes, H1, H2, and H3 receptor blockers were administered to metoprine (10 mg/kg IP)-treated rats. The food and water consumption and urine excretion were measured at 10 and 24 h after the drug administration. It was found that systemic administration of the H3 receptor antagonist, thioperamide (5 mg/kg IP), supplemented the feeding suppressive effect of metoprine. In addition to this, the H1 receptor antagonist mepyramine (20 mg/kg IP) antagonized the suppression of feeding in metoprine-treated rats, whereas the H2 receptor antagonist, ranitidine (100 mg/kg IP), had no effect. Mepyramine also decreased the diuretic response to metoprine, whereas ranitidine or thioperamide were virtually without effect. The present results show that elevation of brain histamine content by inhibiting the catabolism of histamine suppresses food intake, and this effect of metoprine can be abolished by pretreatment with antihistamines. Although the blockade of H1 receptors also attenuates the diuretic response to metoprine, further studies are needed to understand the mechanisms that mediate the effects of metoprine on water balance.