Modulation of morphine-induced antinociception in mice by histamine H3-receptor ligands.
The effects of compounds active at histamine H3-receptors on morphine-induced antinociception have been investigated in thermal and chemical tests in mice; tail-immersion (50 degrees C) and hot-plate (49 degrees and 55 degrees C) tests and acetic acid-induced writhing. Neither (R)alpha-methylhistamine, a specific agonist, (S)alpha-methylhistamine, a chemical control, nor thioperamide, an antagonist, had any antinociceptive action alone but thioperamide (3 mg kg-1) attenuated the effects of morphine in the tail-immersion test while (R)alpha-methylhistamine (1 mg kg-1), but not the (S) isomer, potentiated its effects in the hot-plate test at 55 degrees C. These results are consistent with the morphine potentiation seen with H1-antagonists and suggest that central histaminergic mechanisms can modulate opioid actions.
Department of Life Sciences, University of East London, U.K.
S M
SM
Owen
G
G
Sturman
P
P
Freeman
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D005260:Female; D017442:Histamine Agonists; D006633:Histamine Antagonists; D006358:Hot Temperature; D051379:Mice; D008818:Mice, Neurologic Mutants; D009020:Morphine / Q000494:pharmacology*; D010146:Pain / Q000139:chemically induced / Q000517:prevention & control; D010147:Pain Measurement / Q000187:drug effects; D018100:Receptors, Histamine H3 / Q000187:drug effects*
D000700:Analgesics; D017442:Histamine Agonists; D006633:Histamine Antagonists; D018100:Receptors, Histamine H3; D009020:Morphine