title: Tris(hydroxymethyl)aminomethane inhibits calcium uptake in vascular smooth muscle.
abstract: This report demonstrates that the commonly used buffering agent Tris(hydroxymethyl)aminomethane (Tris) in concentrations of 5 and 30 mM inhibits calcium (Ca2+) uptake in both rat aortic and portal venous smooth muscle. The data indicates that total exchangeable Ca2+ in portal vein is reduced by about 35% in 5 or 30 mM Tris, while the intracellular exchangeable Ca2+ is not significantly altered. On the other hand, in aortic smooth muscle, while 30 mM Tris reduces total exchangeable Ca2+ by about 20%, intracellular Ca2+ is reduced by 44% in 5 mM Tris and by 55% in 30 mM Tris. The present studies, thus, reveal that Tris exerts significant inhibitory effects on exchangeability and transmembrane movement of Ca2+ in at least two different types of smooth muscle.
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism*; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D009928:Organ Specificity; D011169:Portal Vein / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D014325:Tromethamine / Q000494:pharmacology*
chemical_list: D014325:Tromethamine; D002118:Calcium