AJP - Gastrointestinal and Liver Physiology, Vol 257, Issue 4 578-G583, Copyright © 1989 by American Physiological Society
Phorbol esters induce retrograde myoelectric activity in rabbit ileum in vivo
R. H. Davis and J. R. Mathias
Department of Medicine, University of Florida, Gainesville 32610.
We demonstrated a unique myoelectric response to phorbol esters and a
diacylglycerol, 1-oleoyl-2-acetyl-snglycerol, in rabbit ileal loops. This
retrograde activity, the orad migrating complex (OMC), was devoid of
slow-wave distortion or alterations in slow-wave frequency. The OMC was not
inhibited by the cyclooxygenase inhibitor indomethacin or enhanced by
addition of the calcium ionophore A23187. The OMC occurred after 4
beta-phorbol 12-myristate 13-acetate, a phorbol ester known to activate
protein kinase C, and after 4 alpha-phorbol 12,13-didecanoate, one that
does not. Therefore, these studies provide initial evidence that the
myoelectric activity induced by phorbol esters and a diacylglycerol is most
likely in addition to the activation of protein kinase C.
