AJP - Cell Physiology, Vol 263, Issue 4 C896-C900, Copyright © 1992 by American Physiological Society
Lysophosphatidic acid induces a pertussis toxin-sensitive Ca(2+)-activated Cl- current in Xenopus laevis oocytes
M. E. Durieux, M. N. Salafranca, K. R. Lynch and J. R. Moorman
Department of Anesthesiology, University of Virginia Health Sciences Center, Charlottesville 22908.
Lysophosphatidic acid (LPA) induces a Ca(2+)-activated Cl- current in
defolliculated Xenopus laevis oocytes. The response appears mediated by a
specific membrane receptor, because no current is induced when related
compounds [phosphatidic acid (PA), lysophosphatidylcholine (LPC), and
lysophosphatidylserine (LPS)] are applied extracellularly or when LPA is
injected intracellularly. Incubation in pertussis toxin prevents the
response. The response is mediated by a Ca(2+)-activated Cl- current
because 1) it is abolished by intracellular ethylene
glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA; 5 mM)
but not affected by changes in extracellular Ca2+ concentration and 2) the
reversal potential becomes more positive at lower Cl- concentrations.
Suramin (2 mM) blocks the LPA-induced current, but PA, LPS, LPC, and the
platelet-activating factor antagonist WEB-2086 do not. The response is dose
dependent for LPA concentrations from 10(-8) to 10(-3) M. Incubation of
oocytes in LPA does not induce germinal vesicle breakdown. These findings
suggest that this novel oocyte response to LPA is mediated by a specific
membrane receptor linked to a pertussis toxin-sensitive G protein.
