H3 receptor-mediated inhibition of the neurogenic vasopressor response in pithed rats.
In pithed rats, the H3 agonist R-(-)-alpha-methylhistamine (R alpha MeHA) inhibited the electrically induced increase in blood pressure without affecting the vasopressor response to exogenous noradrenaline. The effect of R alpha MeHA was not affected by the H1 and H2 antagonists dimetindene and ranitidine, but attenuated by the H3 antagonist thioperamide. At higher doses, R alpha MeHA itself increased basal blood pressure; this effect was not affected by the H1, H2 and H3 antagonists. In conclusion, the neurogenic vasopressor response can be modulated via H3 receptors, probably located presynaptically on postganglionic sympathetic nerve fibres.
Malinowska
B
B
Institut für Pharmakologie und Toxikologie, Universität Bonn, F.R.G.
Schlicker
E
E
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology; D009412:Nerve Fibers / Q000648:ultrastructure*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011968:Receptors, Histamine / Q000502:physiology*; D018100:Receptors, Histamine H3; D013564:Sympathetic Nervous System / Q000648:ultrastructure*; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology
D008761:Methylhistamines; D011968:Receptors, Histamine; D018100:Receptors, Histamine H3; C069357:alpha-methylhistamine; D009638:Norepinephrine