title: Pharmacological action of 5'-methylthioadenosine on isolated rabbit aorta strips.
abstract: The effects of 5'-methylthioadenosine (MTA) and adenosine analogues on isolated rabbit thoracic aorta strips were studied in vitro. High concentrations (500-1,000 microM) of adenosine analogues produced dose-dependent relaxation in isolated rabbit thoracic aorta strips. The relative potencies of relaxant effect were MTA greater than N6-phenylisopropyladenosine greater than 2-chloroadenosine on a molar basis. MTA (50-1,000 microM) suppressed the contraction induced by norepinephrine in isolated rabbit thoracic aorta strips in a concentration-dependent manner. Nucleoside uptake inhibitor dipyridamole did not impair the MTA actions. Pretreatment of the aorta strips with theophylline, an adenosine receptor antagonist, blocked the actions of MTA. MTA showed a relaxant effect in KCl-contracted aorta suggesting that MTA did not affect the metabolism or reuptake of norepinephrine. The present experiments suggest that MTA has a pharmacological action on the arterial smooth muscle cells mediated through adenosine receptors.
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects*; D003839:Deoxyadenosines; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D051381:Rats; D011956:Receptors, Cell Surface / Q000187:drug effects; D011983:Receptors, Purinergic; D013872:Thionucleosides / Q000494:pharmacology*
chemical_list: D003839:Deoxyadenosines; D011956:Receptors, Cell Surface; D011983:Receptors, Purinergic; D013872:Thionucleosides; C008500:5'-methylthioadenosine; D000241:Adenosine