AJP - Cell Physiology, Vol 256, Issue 3 C495-C500, Copyright © 1989 by American Physiological Society

ARTICLES

ANP relaxes bovine tracheal smooth muscle and increases cGMP

K. Ishii and F. Murad
Department of Medicine, Stanford University School of Medicine, Palo Alto, California 94304.

Effects of atrial natriuretic peptides (ANP) on the tension, content of guanosine 3',5'-cyclic monophosphate (cGMP) and adenosine 3',5'-cyclic monophosphate (cAMP) and activity of particulate and soluble forms of guanylate cyclase were examined in bovine tracheal smooth muscle. Atrial natriuretic factor (ANF), atriopeptin II, and atriopeptin III were found to induce relaxation of tracheal smooth muscle precontracted with 5 x 10(-8) M carbachol (an approximate median effective concentration) in a concentration-dependent manner. However, atriopeptin I failed to induce significant relaxation of the muscle. Similar results were obtained when 3 x 10(-6) M histamine or 5 x 10(-7) M serotonin was used as the contracting agent. However, the relaxant effects of ANF, atriopeptin II, and atriopeptin III were much less when a higher concentration of carbachol or 30 mM K+ was used as the contractile agent. Maximally inhibitory concentration (IC50) values of ANF, atriopeptin II, and atriopeptin III for inhibition of muscle contraction induced by 5 x 10(-8) M carbachol ranged from 3.8 to 8.3 x 10(-9) M, indicating that these peptides have intermediate potency between isoproterenol (IC50, 2.0 x 10(-9) M) and sodium nitroprusside (IC50, 2.0 x 10(-8) M). Treatment of the muscle with 3 x 10(-7) M ANF slowed the rate of tension development of the muscle by 10(-7) M carbachol. Tissue levels of cAMP were not influenced by any of the atrial peptides at concentrations of 10(-9)-10(-6) M; however, cGMP levels were increased about five- to ninefold.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				A. M. Hamad, A. Clayton, B. Islam, and A. J. Knox Guanylyl cyclases, nitric oxide, natriuretic peptides, and airway smooth muscle function Am J Physiol Lung Cell Mol Physiol, November 1, 2003; 285(5): L973 - L983. [Abstract] [Full Text] [PDF]

				E. H. Rho, W. J. Perkins, R. R. Lorenz, D. O. Warner, and K. A. Jones Differential effects of soluble and particulate guanylyl cyclase on Ca2+ sensitivity in airway smooth muscle J Appl Physiol, January 1, 2002; 92(1): 257 - 263. [Abstract] [Full Text] [PDF]

				P. J. BARNES Pharmacology of Airway Smooth Muscle Am. J. Respir. Crit. Care Med., November 1, 1998; 158(2007): S123 - S132. [Abstract] [Full Text] [PDF]

				A. M. Hamad, S. Range, E. Holland, and A. J. Knox Regulation of cGMP by soluble and particulate guanylyl cyclases in cultured human airway smooth muscle Am J Physiol Lung Cell Mol Physiol, October 1, 1997; 273(4): L807 - L813. [Abstract] [Full Text] [PDF]

				X.-B. Zhou, P. Ruth, J. Schlossmann, F. Hofmann, and M. Korth Protein Phosphatase 2A Is Essential for the Activation of Ca2+-activated K+ Currents by cGMP-dependent Protein Kinase in Tracheal Smooth Muscle and Chinese Hamster Ovary Cells J. Biol. Chem., August 16, 1996; 271(33): 19760 - 19767. [Abstract] [Full Text] [PDF]