AJP - Heart and Circulatory Physiology, Vol 271, Issue 1 267-H272, Copyright © 1996 by American Physiological Society

ARTICLES

Myogenic responses of isolated rat skeletal muscle venules: modulation by norepinephrine and endothelium

G. Dornyei, E. Monos, G. Kaley and A. Koller
Clinical Research Department, Semmelweis University of Medicine, Budapest, Hungary.

The pressure-induced myogenic response of large venules of skeletal muscle and its possible interactions with adrenergic receptor activation and endothelial factors have not yet been elucidated. Therefore, first-order venules of rat gracilis muscle were isolated, cannulated, and placed in an organ chamber. Changes in internal diameter of the vessels as a function of perfusion pressure (PP) were obtained. In response to increases in PP (0.5-17.5 mmHg), the diameter of venules increased from 197.1 +/- 23.96 to 369 +/- 14.1 microns. In passive conditions (in Ca(2+)-free solution), the pressure-diameter curve of venules shifted significantly upward. In the presence of norepinephrine (NE; 10(-6) M) in the bath solution, the pressure-diameter curve of active venules shifted significantly downward, and in the pressure-normalized diameter curve, a negative slope developed (-6.1 +/- 4.6). In both the absence and presence of NE, removal of endothelium significantly reduced venular diameters in the pressure ranges of 3-5 and 2-5 mmHg, respectively, but did not change significantly the characteristics of the pressure-diameter curves. These findings indicate that the smooth muscle of venules actively responds to changes in intraluminal pressure. This response is greatly facilitated by NE and modulated by the endothelium. The myogenic response of skeletal muscle venules, especially in the presence of NE, could have a role in the regulation of the resistance and capacitance of venules and, consequently, blood flow and tissue exchange in skeletal muscle.

This article has been cited by other articles:

				E. Sandblom and M. Axelsson Venous hemodynamic responses to acute temperature increase in the rainbow trout (Oncorhynchus mykiss) Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2007; 292(6): R2292 - R2298. [Abstract] [Full Text] [PDF]

				A. Kitano, J. K. Shoemaker, M. Ichinose, H. Wada, and T. Nishiyasu Comparison of cardiovascular responses between lower body negative pressure and head-up tilt J Appl Physiol, June 1, 2005; 98(6): 2081 - 2086. [Abstract] [Full Text] [PDF]

				E. Monos, M. Lorant, G. Dornyei, V. Berczi, and G. Nadasy Long-Term Adaptation Mechanisms in Extremity Veins Supporting Orthostatic Tolerance Physiology, October 1, 2003; 18(5): 210 - 214. [Abstract] [Full Text] [PDF]

				Z. L. S. Brookes and S. Kaufman Myogenic responses and compliance of mesenteric and splenic vasculature in the rat Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2003; 284(6): R1604 - R1610. [Abstract] [Full Text] [PDF]

				E. Monos, M. Lorant, and E. Feher Influence of long-term experimental orthostatic body position on innervation density in extremity vessels Am J Physiol Heart Circ Physiol, October 1, 2001; 281(4): H1606 - H1612. [Abstract] [Full Text] [PDF]

				V. A. Imadojemu, M. E. J. Lott, K. Gleeson, C. S. Hogeman, C. A. Ray, and L. I. Sinoway Contribution of perfusion pressure to vascular resistance response during head-up tilt Am J Physiol Heart Circ Physiol, July 1, 2001; 281(1): H371 - H375. [Abstract] [Full Text] [PDF]

				J. J. Bishop, P. R. Nance, A. S. Popel, M. Intaglietta, and P. C. Johnson Diameter changes in skeletal muscle venules during arterial pressure reduction Am J Physiol Heart Circ Physiol, July 1, 2000; 279(1): H47 - H57. [Abstract] [Full Text] [PDF]

				L. Loufrani, S. Lehoux, A. Tedgui, B. I. Levy, and D. Henrion Stretch Induces Mitogen-Activated Protein Kinase Activation and Myogenic Tone Through 2 Distinct Pathways Arterioscler. Thromb. Vasc. Biol., December 1, 1999; 19(12): 2878 - 2883. [Abstract] [Full Text] [PDF]

				A. Koller, R. Mizuno, and G. Kaley Flow reduces the amplitude and increases the frequency of lymphatic vasomotion: role of endothelial prostanoids Am J Physiol Regulatory Integrative Comp Physiol, December 1, 1999; 277(6): R1683 - R1689. [Abstract] [Full Text] [PDF]

				R. Mizuno, N. Ono, and T. Ohhashi Involvement of ATP-sensitive K+ channels in spontaneous activity of isolated lymph microvessels in rats Am J Physiol Heart Circ Physiol, October 1, 1999; 277(4): H1453 - H1456. [Abstract] [Full Text] [PDF]

				A. Koller, G. Dornyei, and G. Kaley Flow-induced responses in skeletal muscle venules: modulation by nitric oxide and prostaglandins Am J Physiol Heart Circ Physiol, September 1, 1998; 275(3): H831 - H836. [Abstract] [Full Text] [PDF]

				R. Mizuno, A. Koller, and G. Kaley Regulation of the vasomotor activity of lymph microvessels by nitric oxide and prostaglandins Am J Physiol Regulatory Integrative Comp Physiol, March 1, 1998; 274(3): R790 - R796. [Abstract] [Full Text] [PDF]