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Electrophysiological responses to bradykinin and microinjected inositol polyphosphates in neuroblastoma cells : Possible role of inositol 1,3,4-trisphosphate in altering membrane potential

Electrophysiological responses to bradykinin and microinjected inositol polyphosphates in neuroblastoma cells : Possible role of inositol 1,3,4-trisphosphate in altering membrane potential

Authors :
Wouter H. Moolenaar
Leon G.J. Tertoolen
B. C. Tilly
R F Irvine
Source :
FEBS Letters, 214(2), 365. Elsevier
Publication Year :
1987

Abstract

Addition of bradykinin to mouse N1E-115 neuroblastoma cells evokes a rapid but transient rise in cytoplasmic free Ca2+ concentration ([Ca2+]i). The [Ca2+]i rise is accompanied by a transient membrane hyperpolarization, due to a several-fold increase in K+ conductance, followed by a prolonged depolarizing phase. Pre-treatment of the cells with a Ca2+-ionophore abolishes the hormone-induced hyperpolarization but leaves the depolarizing phase intact. The transient hyperpolarization can be mimicked by iontophoretic injection of IP3(1,4,5) or Ca2+, but not by injection of IP3(1,3,4), IP4(1,3,4,5) or Mg2+ into the cells. Instead, IP3(1,3,4) evokes a small but significant membrane depolarization in about 50% of the cells tested. Microinjected IP4(1,3,4,5) has no detectable effect, nor has treatment of the cells with phorbol esters. These results suggest that, while IP3(1,4,5) triggers the release of stored Ca2+ to hyperpolarize the membrane, IP3(1,3,4) may initiate a membrane depolarization.

Details

Language :
English
ISSN :
00145793
Database :
OpenAIRE
Journal :
FEBS Letters, 214(2), 365. Elsevier
Accession number :
edsair.doi.dedup.....950617cc93cfb01542c16327779b0a02