title: The cardiovascular actions of 1-methylisoguanosine.
abstract: 1. 1-Methylisoguanosine was found to cause a potent long-lasting decrease in both blood pressure and heart rate after oral administration to conscious hypertensive rats. Dose-response curves to intravenously administered 1-methylisoguanosine and adenosine in anaesthetized rats demonstrated qualitatively similar decreases in blood pressure and heart rate, with 1-methylisoguanosine being two to three times more potent than adenosine. 2. In guinea-pig isolated atria, 1-methylisoguanosine exhibited a negative inotropic and a negative chronotropic effect with a greater potency than adenosine. 3. In halothane-anaesthetized cats, 1-methylisoguanosine produced a biphasic response on cardiac output: a rapid initial decrease followed by a slow increase. 4. 1-Methylisoguanosine had no effect on the response to intralumenally administered noradrenaline in isolated perfused rat tail arteries but reduced the response to electrical stimulation. In these effects, 1-methylisoguanosine was similar to adenosine.
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D002302:Cardiac Output / Q000187:drug effects; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005260:Female; D006151:Guanosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010477:Perfusion; D051381:Rats
chemical_list: D000959:Antihypertensive Agents; D006151:Guanosine; C022591:doridosine; D000241:Adenosine