AJP - Heart and Circulatory Physiology, Vol 273, Issue 3 1493-H1501, Copyright © 1997 by American Physiological Society

ARTICLES

Hemodynamic effects of L- and D-S-nitroso-beta,beta-dimethylcysteine in rats

M. D. Travis, R. L. Davisson, J. N. Bates and S. J. Lewis
Cardiovascular Center, University of Iowa, Iowa City 52242, USA.

This study examined whether S-nitroso-beta,beta-dimethylcysteine (S-nitrosopenicillamine; SNPEN) may activate stereoselective S-nitrosothiol receptors within the vasculature. We examined 1) the hemodynamic effects produced by the L- and D-isomers of SNPEN (12.5-400 nmol/kg iv), the L- and D-isomers of the parent thiols [L- and D-penicillamine (PEN); 12.5-400 nmol/kg iv], and the nitric oxide (NO) donor sodium nitroprusside (SNP; 1-10 micrograms/kg iv) in conscious rats; 2) the hemodynamic effects produced by these compounds in urethan-anesthetized rats; and 3) the relative decomposition of L- and D-SNPEN to NO on addition to rat blood or cultured porcine aortic smooth muscle (PASM) cells. We found that 1) L-SNPEN was a more potent hypotensive and vasodilator agent within the mesenteric bed and within sympathetically intact and sympathetically denervated hindlimb beds of conscious rats than was D-SNPEN; 2) the hypotension and vasodilation produced by L-SNPEN was similar in conscious and anesthetized rats, whereas the effects of D-SNPEN and SNP were augmented by urethan-anesthesia; 3) L- and D-PEN did not affect hemodynamic parameters in conscious or anesthetized rats; and 4) L- and D-SNPEN decomposed equally to NO on addition to rat blood or PASM cells. These results suggest that the vasodilator effects of SNPEN involve the interaction of this S-nitrosothiol with stereoselective recognition sites within the vasculature and that urethan alters the mechanisms by which L- and D-SNPEN relax vascular smooth muscle.

This article has been cited by other articles:

				E. J. Whalen, A. K. Johnson, and S. J. Lewis Tachyphylaxis to PACAP-27 after inhibition of NO synthesis: a loss of adenylate cyclase activation Am J Physiol Regulatory Integrative Comp Physiol, November 1, 1999; 277(5): R1453 - R1461. [Abstract] [Full Text] [PDF]

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