Effects of H2-blockers on rat mesenteric arterioles under resting conditions.
H2-receptor but not H1-receptor antagonists, administered by intravenous infusion, produce a dose-dependent constriction of superior mesenteric arterioles of the anaesthetized rat under resting conditions. However the possibility that this effect could be related to a blockade of H2 receptors is unlikely, since their potency on blood flow changes does not parallel known H2-receptor antagonist activity. Furthermore, the estimated potency ratio is not in the expected order if the vasoconstriction is due to H2-antagonism, the potency ratios on guinea-pig atrial muscle and on mouse gastric acid secretion being famotidine greater than oxmetidine greater than ranitidine greater than cimetidine.
Morini
G
G
Institute of Pharmacology, University of Parma, Italy.
Chiavarini
M
M
Barocelli
E
E
Impicciatore
M
M
D000758:Anesthesia; D000818:Animals; D001160:Arterioles / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006635:Histamine H2 Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D007262:Infusions, Intravenous; D007275:Injections, Intravenous; D008638:Mesenteric Arteries / Q000187:drug effects*; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D006635:Histamine H2 Antagonists; D011738:Pyrilamine