Relationship between contractile responses and cytosolic free calcium levels in response to phorbol ester (PMA) in isolated rat aorta.
We examined the relationship between phorbol ester (PMA)-induced contractile response and cytosolic free calcium level in the rat aorta. PMA (10(-6)M) produced biphasic contraction, i.e., sustained contraction followed by a phasic response superimposed on the sustained contraction. Increase in [Ca2+]i was accompanied by a phasic but not sustained contraction. These results suggest that PMA-induced phasic contraction is dependent on Ca2+ influx but sustained contraction may be due to an increase in Ca2+ sensitivity of contractile protein.
Kamata
K
K
Department of Physiology and Morphology, Chemistry, Hoshi University, Shinagawa-ku, Tokyo 142, Japan.
Suenaga
H
H
Chikada
S
S
Kasuya
Y
Y
D000818:Animals; D001011:Aorta / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D010703:Phorbol Esters / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D010703:Phorbol Esters; D002118:Calcium