Effects of strongly anisosmotic and NaCl deficient solutions on muscimol- and glutamate evoked whole-cell currents in freshly dissociated hippocampal neurons.

Journal Article

Sudden exposure of dissociated hippocampal neurons to strongly hypo- or hyperosmotic solutions suppresses voltage gated Na+, K+ and Ca2+ currents. We investigated whether ligand gated ion currents were similarly shut down by exposure to anisosmotic solutions. The effect of hypo-osmotic, NaCl deficient (mannitol-substituted), or hyper-osmotic test solutions delivered from a flow pipette was tested on voltage gated Ca2+ currents and on currents and conductance changes evoked by brief administration of either the GABAA-agonist muscimol or glutamate. Hyper-osmotic solution caused cells to shrink, but cell membrane capacitance did not change. Muscimol-induced conductance increases were depressed by hypo-osmotic and by NaCl deficient solutions and often by hyper-osmotic solution. Voltage gated Ca2+ currents were depressed by anisosmotic, but not by NaCl deficient isosmotic solution. NMDA- and non-NMDA evoked conductance increases were depressed by hyperosmotic solution; hypo-osmotic and NaCl deficient solutions were not tested on glutamate induced currents. Ligand gated currents are suppressed by anisosmotic solutions more slowly than are voltage gated channels. The changes caused by anisosmotic and NaCl deficient solutions were much greater then expected from calculated electrochemical effects and are probably the result of change in receptor controlled channels.

Full Text

Duke Authors

Cited Authors

  • Vreugdenhil, M; Somjen, GG; Wadman, WJ

Published Date

  • January 23, 1995

Published In

Volume / Issue

  • 670 / 1

Start / End Page

  • 89 - 96

PubMed ID

  • 7536614

International Standard Serial Number (ISSN)

  • 0006-8993

Language

  • eng

Conference Location

  • Netherlands