AJP - Heart and Circulatory Physiology, Vol 270, Issue 2 442-H446, Copyright © 1996 by American Physiological Society

ARTICLES

Local cholinergic mechanisms mediate nitric oxide-dependent flow-induced vasorelaxation in vitro

C. M. Martin, A. Beltran-Del-Rio, A. Albrecht, R. R. Lorenz and M. J. Joyner
Department of Anesthesiology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.

To determine whether local cholinergic mechanisms evoke nitric oxide (NO)-mediated flow-induced vasorelaxation, canine coronary artery rings without endothelium were suspended beneath an organ chamber that contained a stainless steel tube and a femoral artery segment with endothelium. The rings were superfused at a basal rate of 1 ml/min with physiological salt solution that was bubbled with 95% O2-5% CO2 and maintained at 37 degrees C. They were stretched to optimal length and contracted with prostaglandin F 2 alpha (2 x 10(-6) M). When flow through the stainless steel tube (direct superfusion) was increased from the basal rate of 1 to 4 ml/min, coronary force did not change. Superfusion of the rings (n = 8) with effluent from the femoral segment (endothelial superfusion) at 4 ml/min to study flow-induced vasodilation caused a 67.3 +/- 10.8% relaxation. Treatment of the segment with the NO synthase blocker NG-monomethyl-L-arginine (10(-4) M) eliminated the relaxation seen during endothelial superfusion (P < 0.05 vs. control). Application of atropine (10(-6) M) to additional femoral segments (n = 8) abolished the coronary relaxation observed during endothelial superfusion at 1 ml/ min, and the flow-induced relaxation observed at 4 ml/min was reduced from 64 +/- 8.3 to 27 +/- 5.6% (P < 0.05 vs. control). In studies on additional segments and rings (n = 6), the flow-induced relaxations at 4 ml/min of endothelial superfusion were blunted from 86 +/- 10 to 28 +/- 13% after the segments were treated with acetylcholinesterase (0.00028 U/min for 20 min). These data indicate that basal- and flow-induced release of NO from the vascular endothelium can be mediated by local cholinergic mechanisms. It is possible that flow causes acetylcholine release from certain endothelial cells, which stimulates NO release from these cells or from neighboring endothelial cells.

This article has been cited by other articles:

				T. Miyauchi, S. Maeda, M. Iemitsu, T. Kobayashi, Y. Kumagai, I. Yamaguchi, and M. Matsuda Exercise causes a tissue-specific change of NO production in the kidney and lung J Appl Physiol, January 1, 2003; 94(1): 60 - 68. [Abstract] [Full Text] [PDF]

				C. J. Jen, S.-J. Jhiang, and H.-I. Chen Cellular Responses to Mechanical Stress: Invited Review: Effects of flow on vascular endothelial intracellular calcium signaling of rat aortas ex vivo J Appl Physiol, October 1, 2000; 89(4): 1657 - 1662. [Abstract] [Full Text] [PDF]

				B. A. KINGWELL Nitric oxide-mediated metabolic regulation during exercise: effects of training in health and cardiovascular disease FASEB J, September 1, 2000; 14(12): 1685 - 1696. [Abstract] [Full Text]

				S. Shastry, C. T. Minson, S. A. Wilson, N. M. Dietz, and M. J. Joyner Effects of atropine and L-NAME on cutaneous blood flow during body heating in humans J Appl Physiol, February 1, 2000; 88(2): 467 - 472. [Abstract] [Full Text] [PDF]

				G. Radegran and B. Saltin Nitric oxide in the regulation of vasomotor tone in human skeletal muscle Am J Physiol Heart Circ Physiol, June 1, 1999; 276(6): H1951 - H1960. [Abstract] [Full Text] [PDF]

				C. M. ST. CROIX, T. J. WETTER, D. F. PEGELOW, K. C. MEYER, and J. A. DEMPSEY Assessment of Nitric Oxide Formation During Exercise Am. J. Respir. Crit. Care Med., April 1, 1999; 159(4): 1125 - 1133. [Abstract] [Full Text] [PDF]

				R. W. Brock, M. E. Tschakovsky, J. K. Shoemaker, J. R. Halliwill, M. J. Joyner, and R. L. Hughson Effects of acetylcholine and nitric oxide on forearm blood flow at rest and after a single muscle contraction J Appl Physiol, December 1, 1998; 85(6): 2249 - 2254. [Abstract] [Full Text] [PDF]

				S. Shastry, N. M. Dietz, J. R. Halliwill, A. S. Reed, and M. J. Joyner Effects of nitric oxide synthase inhibition on cutaneous vasodilation during body heating in humans J Appl Physiol, September 1, 1998; 85(3): 830 - 834. [Abstract] [Full Text] [PDF]

				M. J. Joyner and N. M. Dietz Nitric oxide and vasodilation in human limbs J Appl Physiol, December 1, 1997; 83(6): 1785 - 1796. [Abstract] [Full Text] [PDF]

				J. K. Shoemaker, J. R. Halliwill, R. L. Hughson, and M. J. Joyner Contributions of acetylcholine and nitric oxide to forearm blood flow at exercise onset and recovery Am J Physiol Heart Circ Physiol, November 1, 1997; 273(5): H2388 - H2395. [Abstract] [Full Text] [PDF]