Effects of 17 beta-estradiol on the responses to vasoactivators and electrical transmural stimulation in isolated dog arteries
Kano, A.
Nihon Hoigaku Zasshi 43(5): 407-415
1989
ISSN/ISBN: 0047-1887 PMID: 2516542 Document Number: 337686
The effects of 17 beta-estradiol, one type of estrogen, on the contractile and relaxant responses associated with the release of TXA2-like and PGI2-like substances activated by vasoactive substances and electrical transmural stimulation in isolated dog arteries were evaluated. The basilar artery and interlober branches of the renal artery were suspended with a tension of 1.5 g, in a tissue organ bath containing 20 ml of Krebs-Henseleit solution, which was maintained at 37 +/- 0.5 degrees C and aerated with a mixture of 95% O2 and 5% CO2, and isotonic changes were recorded. 17 beta-Estradiol increased the contractile response of the basilar artery caused by the release of a TXA2-like substance mediated by muscarinic cholinergic and angiotensin II receptors, and inhibited the relaxant response of the renal artery caused by the release of PGI2-like substance mediated by angiotensin II receptor. It inhibited the relaxant response when PGI2 was exogenously applied to the renal artery. These results indicate that estradiol increases the TXA2/PGI2 ratio. In this study, it was considered that estradiol is involved in the production of TXA2 and PGI2, which can be a cause of vasospasms.