Fukuo K, Morimoto S, Koh E, Yukawa S, Tsuchiya H, Imanaka S, Yamamoto H, Onishi T, Kumahara Y
Biochem Biophys Res Commun. 1986 Apr 14;136(1):247-52. doi: 10.1016/0006-291x(86)90901-0.
The effects of prostaglandin (PG) F2 alpha and 9,11-epithio-11,12-methanothromboxane A2 (STA2), a stable analogue of thromboxane A2, on the cytosolic free calcium concentration ([Ca2+]i) in vascular smooth muscle cells were studied with a new fluorescent Ca2+ indicator fura 2. PGF2 alpha and STA2, which are strong vasoconstrictors, caused rapid phasic and subsequent tonic increases in [Ca2+]i. PGF2 alpha caused dose-dependent elevation of [Ca2+]i not only in control solution but also in the calcium-free solution. A first stimulation with PGF2 alpha caused dose-dependent decrease in the response of [Ca2+]i to a second stimulation with PGF2 alpha. Pretreatment with 13-Azaprostanoic acid, a receptor level antagonist of thromboxane A2 inhibited the increase of [Ca2+]i induced by STA2. These results suggest that PGF2 alpha induces calcium mobilization followed by smooth muscle contraction through its specific receptors.
