with indomethacin. Am J Physiol Regulatory Integrative

Comp Physiol 282: R400–R410, 2002; 10.1152/ajpregu.00256. 2001.—We hypothesize that inhibitory effects exist between prostanoids and nitric oxide (NO) in their contributions to cerebral circulation. Piglets (1–4 days old) were divided into three chronically treated (6–8 days) groups: control piglets, piglets treated with indomethacin (75 mg/day), and piglets treated with N-nitro-L-arginine methyl ester (L-NAME, 100 mg kg1 day1). Pial arterioles dilated in response to hyper-capnia similarly among the three groups (41 4, 40 6, and 45 11%). Cerebrospinal fluid cAMP increased in control piglets, while cGMP increased in indomethacin-treated pig-lets. L-NAME, but not 7-nitroindazole, inhibited the response to hypercapnia only in indomethacin-treated piglets (40 6 vs. 17 5%). Topical sodium nitroprusside or iloprost re-stored dilation in response to hypercapnia. Similar result