Parfenova H, Leffler C W
Department of Physiology and Biophysics, University of Tennessee, Memphis 38163, USA.
Eur J Pharmacol. 1995 May 15;278(2):133-42. doi: 10.1016/0014-2999(95)00113-y.
Cerebral vascular reactivity to prostaglandin E2 was investigated in newborn pigs using closed cranial windows. Exogenous prostaglandin E2 is a dilator of pial arterioles that elevates cyclic AMP in cortical cerebrospinal fluid. Pial arterioles are less sensitive to prostaglandin E2 than to the prostacyclin receptor agonist iloprost, but their maximal responses to the dilator prostanoids are similar. The cerebrovascular effects of prostaglandin E2 and iloprost are not additive. Pretreatment with either iloprost or prostaglandin E2 decreases pial arteriolar responsiveness to iloprost without affecting responses to isoproterenol. The homologous desensitization of pial arterioles suggests that auto- and cross-tachyphylaxis in vascular effects of iloprost and prostaglandin E2 occur at the receptor level. Indomethacin, which selectively inhibits prostacyclin receptor-mediated responses in cerebral vascular smooth muscle, greatly reduces the vascular responses to prostaglandin E2. These results suggest that vasodilator effects of prostaglandin E2 in the newborn cerebral circulation are mediated via prostacyclin receptors coupled to adenylyl cyclase.
利用闭合式颅骨视窗研究了新生猪脑血管对前列腺素E2的反应性。外源性前列腺素E2是软脑膜小动脉的扩张剂，可使皮质脑脊液中的环磷酸腺苷升高。软脑膜小动脉对前列腺素E2的敏感性低于对前列环素受体激动剂伊洛前列素的敏感性，但其对扩张性前列腺素类药物的最大反应相似。前列腺素E2和伊洛前列素的脑血管效应并非相加的。用伊洛前列素或前列腺素E2预处理可降低软脑膜小动脉对伊洛前列素的反应性，而不影响其对异丙肾上腺素的反应。软脑膜小动脉的同源脱敏表明，伊洛前列素和前列腺素E2的血管效应中的自身快速耐受性和交叉快速耐受性发生在受体水平。吲哚美辛可选择性抑制脑血管平滑肌中前列环素受体介导的反应，可大大降低对前列腺素E2的血管反应。这些结果表明，前列腺素E2在新生猪脑循环中的血管扩张作用是通过与腺苷酸环化酶偶联的前列环素受体介导的。
