Effects of nitroglycerin on stable thromboxane A2 analogue-induced, nifedipine-resistant contraction in canine basilar artery.
The stable thromboxane A2 analogue, STA2, caused concentration-dependent contractions in the canine basilar artery. In Ca2(+)-free medium containing EGTA (0.1 mM) and nifedipine (10(-6) M), the addition of Ca2+ (2.5 mM) in the presence of STA2 (10(-8) M) caused a tonic contraction (nifedipine-resistant Ca2(+)-induced contraction). In the basilar artery, nitroglycerin did not significantly affect such nifedipine-resistant Ca2(+)-induced contractions, but nearly abolished the contraction in the coronary artery. The present experiments suggest that the regulatory mechanism of mobilized Ca2+ for the nifedipine-resistant Ca2(+)-induced contraction produced by STA2 in the basilar artery is different from that in the coronary artery.
Usui
H
H
Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan.
Akimoto
Y
Y
Kurahashi
K
K
Shirahase
H
H
Fujiwara
M
M
Shibata
S
S
Suzuki
A
A
D000818:Animals; D001488:Basilar Artery / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D003331:Coronary Vessels / Q000187:drug effects; D004285:Dogs; D009119:Muscle Contraction / Q000187:drug effects*; D009543:Nifedipine / Q000494:pharmacology*; D005996:Nitroglycerin / Q000494:pharmacology*; D013928:Thromboxane A2 / Q000494:pharmacology*
D013928:Thromboxane A2; D005996:Nitroglycerin; D009543:Nifedipine; D002118:Calcium