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

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. Pretreatment 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.

• Authors: L G Tertoolen, B C Tilly, R F Irvine, W H Moolenaar
• Journal: FEBS letters (FEBS Lett) Vol. 214 Issue 2 Pg. 365-9 (Apr 20 1987) ISSN: 0014-5793 [Print] England
• PMID: 3494634 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Ethers
• Inositol Phosphates
• Sugar Phosphates
• inositol-1,3,4,5-tetrakisphosphate
• Ionomycin
• Inositol 1,4,5-Trisphosphate
• Bradykinin
• Calcium

Topics

• Animals
• Bradykinin (pharmacology)
• Calcium (metabolism, pharmacology)
• Cell Line
• Electrophysiology
• Ethers (pharmacology)
• Inositol 1,4,5-Trisphosphate
• Inositol Phosphates (pharmacology)
• Ionomycin
• Membrane Potentials (drug effects)
• Microinjections
• Neuroblastoma (physiopathology)
• Sugar Phosphates (pharmacology)