The effect of arachidonic acid on the M current of NG108-15 neuroblastoma × glioma hybrid cells

✍ Scribed by Philippe Béhé; Katrin Sandmeier; Hans Meves

• Publisher: Springer
• Year: 1992
• Tongue: English
• Weight: 775 KB
• Volume: 422
• Category: Article
• ISSN: 0031-6768
• DOI: 10.1007/bf00370411

✦ Synopsis

The M current, IM, a voltage-dependent noninactivating K + current, was recorded in NG108-15 neuroblastoma x glioma hybrid cells, using the wholecell mode of the patch-clamp technique. We studied the effect of arachidonic acid, other fatty acids and inhibitors of the arachidonic acid metabolism. In relatively high concentrations (25-50 gM) arachidonic acid first increased and later decreased the current, I~, which holds the membrane potential at -30 mV and mainly flows through open M channels. It shifted the midpoint potential, Vo, of the relation between M conductance, gM, and membrane potential, V, to more negative values and decreased the maximum conductance gM and the time constant ~M. In smaller concentrations (5-10 gM) arachidonic acid merely decreased Ih and gM with little effect on Vo and ZM-Eicosatetraynoic acid and docosahexaenoic acid acted similarly to arachidonic acid whereas stearic acid had no effect. Of the three enzyme inhibitors studied, nordihydroguaiaretic acid acted similarly to arachidonic acid. i.e. caused a biphasic change in Ih. Indomethacin and quinacrine caused, respectively, a pure increase and a pure decrease of Ih and gM. Possible explanations are build-up of internally produced arachidonic acid, depletion of eicosanoid products or an inhibitory effect unrelated to arachidonic acid metabolism.