AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 2 135-G139, Copyright © 1986 by American Physiological Society
Dose-response effects of indomethacin and PGE2 on electromechanical activity of in vivo rabbit ileum
K. L. Koch, A. Dwyer and G. H. Jeffries
We determined dose-response characteristics of indomethacin and
prostaglandin E2 on the myoelectric activity in ileum of anesthetized New
Zealand White rabbits. Monopolar electrodes and an intraluminal
saline-filled catheter were used to simultaneously record electrical and
mechanical activity. Thirty minutes after injection of 3.0, 5.0, and 10.0
mg/kg indomethacin, the percentage of slow waves with action potentials
increased significantly from 10% to over 80%; at 60 min action potential
activity decreased but remained dose dependent and significantly greater
than controls. Action potential activity correlated with phasic increases
in intraluminal pressure. Low-dose indomethacin (1.5 mg/kg) did not
significantly alter action potential activity. Action potential activity
induced by indomethacin (5 mg/kg) decreased dose dependently after infusion
of prostaglandin E2 (PGE2, 1-28 micrograms/kg). In summary, dose-dependent
action potential activity was induced by indomethacin and reversed by PGE2.
Endogenous inhibitory prostaglandins (PGE2 or others) appear to modulate
activity of specific excitatory neuromuscular circuits in in vivo ileum.
