Effects of indomethacin on changes in renal blood flow induced by adenosine and its analogues in conscious dogs.

The effects of indomethacin on changes in renal blood flow induced by adenosine, NECA (adenosine-5'-N-ethyl-carboxamide) and 2',3'-dinitro-NECA were investigated in 6 chronically instrumented conscious dogs. Adenosine (187.5, 375 and 750 nmol/kg, i.v.) induced a dose-dependent initial decrease, followed by a reactive increase in renal blood flow. NECA (1.5 nmol/kg, i.v.) also induced an initial decrease, which was, however, followed by a prolonged reactive increase in renal blood flow. 2',3'-dinitro-NECA (50 nmol/kg, orally) induced only an increase in renal blood flow. Indomethacin (27.9 mumol/kg, i.v.) caused no relevant change of the initial decrease and a significant attenuation of the reactive increase in renal blood flow induced by adenosine. NECA-induced changes in blood flow were affected by indomethacin in the same direction but to a greater extent than were adenosine-induced changes in blood flow. Indomethacin reversed the increase to a decrease in renal blood flow induced by 2',3'-dinitro-NECA. Thus, prostaglandins seem to be involved in mediating the response of renal blood flow to adenosine, NECA and 2',3'-dinitro-NECA.