AJP - Gastrointestinal and Liver Physiology, Vol 263, Issue 6 953-G959, Copyright © 1992 by American Physiological Society

ARTICLES

Myogenic mechanism for peristalsis in opossum smooth muscle esophagus

J. F. Helm, S. L. Bro, W. J. Dodds, S. K. Sarna and R. G. Hoffmann
Department of Medicine, Medical College of Wisconsin, Milwaukee 53226.

We studied the propagation of phasic contractions initiated by tetraethylammonium (TEA, 1-10 mM), high K+ concentration (10-30 mM), and bethanechol (10(-6) to 10(-2) M) in a whole organ in vitro preparation of the opossum smooth muscle esophagus. TEA initiated phasic contractions that began at all sites along the smooth muscle esophagus and propagated in both directions with a velocity similar to that of primary peristalsis. Blockade of neural transmission by tetrodotoxin (TTX, 10(-7) M) did not prevent contraction propagation. Although a majority of contractions initiated by TEA did not propagate the full length of the esophageal specimen, with the addition of TTX most contractions initiated by TEA did propagate the full specimen length in either direction. High K+ concentration and bethanechol elicited propagated contractions similar to those initiated by TEA. We conclude that 1) a myogenic mechanism exists for propagation of contractions along the smooth muscle esophagus and 2) intramural inhibitory nerves modulate the extent of myogenic propagation in the ascending as well as descending direction. We suggest that esophageal peristalsis may occur by myogenic propagation of contractions that are normally initiated in the proximal smooth muscle esophagus by excitatory nerves. Intramural inhibitory nerves may inhibit retrograde propagation as well as mediate descending inhibition in advance of the peristaltic wave.

This article has been cited by other articles:

				A. Muinuddin, K. Naqvi, L. Sheu, H. Y. Gaisano, and N. E. Diamant Regional differences in cholinergic regulation of potassium current in feline esophageal circular smooth muscle Am J Physiol Gastrointest Liver Physiol, June 1, 2005; 288(6): G1233 - G1240. [Abstract] [Full Text] [PDF]

				A. M. F. Salapatek, J. Ji, and N. E. Diamant Ion channel diversity in the feline smooth muscle esophagus Am J Physiol Gastrointest Liver Physiol, February 1, 2002; 282(2): G288 - G299. [Abstract] [Full Text] [PDF]

				G. R. Wade, L. G. Laurier, H. G. Preiksaitis, and S. M. Sims Delayed rectifier and Ca2+-dependent K+ currents in human esophagus: roles in regulating muscle contraction Am J Physiol Gastrointest Liver Physiol, October 1, 1999; 277(4): G885 - G895. [Abstract] [Full Text] [PDF]

				H. G. Preiksaitis and N. E. Diamant Myogenic mechanism for peristalsis in the cat esophagus Am J Physiol Gastrointest Liver Physiol, August 1, 1999; 277(2): G306 - G313. [Abstract] [Full Text] [PDF]

				B. R. Hurley, H. G. Preiksaitis, and S. M. Sims Characterization and regulation of Ca2+-dependent K+ channels in human esophageal smooth muscle Am J Physiol Gastrointest Liver Physiol, April 1, 1999; 276(4): G843 - G852. [Abstract] [Full Text] [PDF]