Dissociation of actions of BRL 34915 in the rat portal vein.
In rat portal vein, 0.5 and 5.0 microM BRL 34915 [(+/-)-6-cyano-3,4-dihydro-2,2-dimethyl-trans-4-(2-oxo-1-pyrrolidyl++ +)-2H- benzo[b]pyran-3-ol] abolished spontaneous rhythmic movements and norepinephrine (NE)-induced tension responses, respectively. Only the higher (5 microM) concentration of BRL 34915 increased 42K efflux and inhibited the NE-induced increase in 42K efflux. These results suggest that BRL 34915 inhibits spontaneous rhythmic movements and NE-induced tension responses by differing mechanisms of action and that only the block of the NE-induced tension response is related to K+ permeability or conductance changes.
Shetty
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SS
Research Department, Ciba-Geigy Corporation, Summit, NJ 07901.
Weiss
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GB
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001578:Benzopyrans / Q000494:pharmacology*; D019806:Cromakalim; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D011169:Portal Vein / Q000187:drug effects; D011188:Potassium / Q000378:metabolism*; D011197:Potassium Radioisotopes; D011758:Pyrroles / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D000959:Antihypertensive Agents; D001578:Benzopyrans; D011197:Potassium Radioisotopes; D011758:Pyrroles; D019806:Cromakalim; D011188:Potassium; D009638:Norepinephrine