[Substance P depresses GABA-activated currents in cultured hippocampal pyramidal neurons of rats].
The purpose of the present study was to explore whether substance P (SP) modulates the response mediated by GABAA receptors. Experiments were carried out on cultured hippocampal pyramidal neurons of rats. GABA-activated inward currents were recorded using the whole-cell-patch-clamp technique. The majority of the neurons examined (66/92, 72%) were sensitive to both GABA and SP. When the neurons were treated with SP prior to application of GABA, the GABA-activated current (IGABA) was inhibited markedly, which was concentration-dependent and could be blocked by spantide, an NK1 receptor antagonist. With 10(-8), 10(-7), 10(-6) and 10(-5) mol/L SP, IGABA was inhibited by 18%, 24.8%, 25.9% and 28% respectively. Intracellular application of H7, a potent inhibitor of PKC, abolished inhibition of IGABA by SP, suggesting that the inhibition of IGABA by SP may be a result of intracellular phosphorylation of the GABAA receptor.
Xiong
S H
SH
Department of Physiology, Yunyang Medical College, Shiyan 442000.
Li
Z W
ZW
Fan
Y Z
YZ
Wang
M J
MJ
Wei
J B
JB
D000818:Animals; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D058787:GABA-A Receptor Antagonists; D008564:Membrane Potentials / Q000187:drug effects; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000502:physiology*; D013373:Substance P / Q000494:pharmacology*
D058787:GABA-A Receptor Antagonists; D011963:Receptors, GABA-A; D013373:Substance P