| Abstrakt: |
The effects of intrarenal infusion of prostaglandins (PGs) of the E, A and F series on renal vascular resistance and on vasoconstrictor responses to renal nerve stimulation (RNS), norepinephrine (NE) and angiotensin (A) were determined in the in situ feline kidney under conditions of controlled blood flow. Infusion of PGE2 (3 and 0.3 mug/min) and PGE1 (3 mug/min) resulted in a marked decrease in renal perfusion pressure and a reduction in responses to all vasoconstrictor stimuli. PGE2 (0.03 mug/min) did not alter perfusion pressure. However, responses to RNS and A but not to NE were attenuated. PGA2 (3 and 0.3 mug/min) had no significant effect on perfusion pressure. PGA1 (3 mug/min) resulted in a transient decrease in renal vascular resistance which was not maintained during the infusion period. PGA2 (3 mug/min) reduced the response to RNS at 10 and 30 cps and reduced the response to A, whereas responses to NE were not affected. PGA2 (0.3 mug/min) had no effect on responses to either of the pressor stimuli. PGA1 infusion resulted in an enhanced response to RNS at the highest stimulus frequency and decreased the response elicited by A. PGF2alpha (3 mug/min) had no significant effect on renal vascular resistance or on responses to NE and nerve stimulation. However, the response to angiotensin was decreased and responses to RNS at 10 and 30 cps were decreased 30 minutes after the PGF2alpha infusion. The present data demonstrate that, of the natural renal PGs, PGE2 and PGA2 possess the capacity to modulate the effects of the sympathetic nervous system on the feline kidney. In addition, the effects of PGE and PGA on responses to adrenergic stimuli and on vascular resistance could be separated. |
