Muscarinic receptor subtypes mediate vasorelaxation in isolated XXXX deep dorsal penile vein.

@entity10258 @entity1641 @entity1617 @entity2647 @entity3897 @entity4140 @entity5402 @entity934
OBJECTIVES: To investigate the effect of @entity934 ( @entity1617 ) on @entity1641 deep dorsal penile vein and to characterize the muscarinic receptor subtypes involved in this response. METHODS: Vein rings were mounted in an organ bath chamber, and the isometric tension was recorded. RESULTS: In @entity2647 -contracted veins, @entity1617 (1 nM to 1 microM) induced endothelium-dependent relaxation. The muscarinic receptor antagonist, @entity3897 , produced parallel rightward shifts of the @entity1617 response curves (pA2 = 10.04; pK(B) = 9.98). @entity5402 (10 nM to 100 microM) also evoked relaxation in the vein segments, but showed a lower potency and similar relaxation to that induced by @entity1617 . @entity4140 , the high, intermediate, and low-affinity antagonist for M1, M3, and M2 receptors, respectively, inhibited @entity1617 and @entity5402 -induced relaxation, yielding pA2 values of 7.51 and 7.37, and pK(B) values of 7.38 and 7.28, respectively. @entity10258 , a high-affinity M2 antagonist, showed no significant effect on the response to @entity1617 . However, a high-affinity M3 antagonist, pFHHSiD, potently blocked the relaxation induced by @entity5402 and @entity1617 , yielding pA2 and pK(B) values of 7.72 and 7.70 for pFHHSiD against @entity1617 , respectively, and of 7.77 and 7.65 against @entity5402 , respectively. CONCLUSIONS: These results indicate that @entity1617 induces an endothelium-dependent relaxation in @entity1641 deep dorsal penile vein. The antagonist profile suggests that M3 muscarinic receptors mediate @entity1617 -induced relaxation in this tissue.
