Jpn. J. Pharmacol. 71 (2), 109-112 (1996)

The Role of Histamine H1-Receptors in the Anticonvulsive Effect of Morphine against Maximal Electroconvulsive Shock in Mice

Cetin Hakan Karadag, Ahmet Ulugol, Dikmen Dokmeci and Ismet Dokmeci

Department of Pharmacology, Faculty of Medicine, Trakya University, 22030, Edirne, Turkey

Abstract: Morphine is known to release histamine from mast cells. It is also known that histamine receptors mediate some of morphine's effects on the central nervous system. The contribution of H1- and H2-receptors to the effect of morphine on maximal electroconvulsive shock in mice was investigated in the present experiments. Morphine showed a dose-dependent anticonvulsive effect, but produced spontaneous clonic convulsions at higher doses (100 mg/kg, i.p.). The anticonvulsive effect of morphine (1 mg/kg, i.p.) was antagonized by histamine H1-receptor antagonists, dimethindene (0.1 mg/kg, i.p.), promethazine (0.4 mg/kg, i.p.) and pheniramine (30 mg/kg, i.p.), and naloxone (10 mg/kg, i.p.), but not by the H2-receptor antagonist ranitidine (10 - 50 microg, i.c.v.). These results show that morphine has an anticonvulsive effect via histamine H1-receptors against maximal electroconvulsive shock in mice.

Keywords: Morphine, Anticonvulsive effect, Histamine, Histamine H1-receptor, Maximal electroconvulsive shock

Copyright© The Japanese Pharmacological Society 1996

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