The role of prostaglandins (PGs) and baroreflex in the pressor response to norepinephrine (NE) were examined in one-kidney, one clip rabbits with renal artery stenosis for 3-day' s duration (3-day clipped rabbits) and in sham operated rabbits with one-kidney without renal artery stenosis.
An exaggerated pressor response to NE, 800ng/kg/min, was observed in the 3-day clipped rabbits, and it was abolished by angiotensin II antagonist, [Sar
1, Ile
8] angiotensin II (AIIA). Treatment with indomethacin, 10mg/kg, induced hyperresponsiveness to NE in the sham operated rabbits and also produced a further increase in the response in the 3-day clipped rabbits : the enhanced responses with similar levels were not attenuated by AIIA in either group. A subdepressor dose of PG E
2, 800ng/kg/min, abolished the hyperresponsiveness in the 3-day clipped rabbits, while a subdepressor or depressor dose of PG I
2, 10 or 20 ng/kg/min did not. However, the concurrent infusion of AIIA with PG I
2 attenuated the hyperresponsiveness.
Baroreflex, which was calculated from the response of blood pressure and pulse interval to the injection of phenylephrine and nitroglycerin, was not different between the 3-day clipped rabbits and the sham operated rabbits.
These results indicate that the PGs, particularly PG E
2, may be and the baroreflex may not be involved in the enhanced pressor response to NE in the 3-day clipped rabbits, in addition to the altered renin-angiotensin system.
抄録全体を表示