The actions of intermediate and long-chain n-alkanols on unitary NMDA currents in hippocampal neurons.

The actions of the n-alkanols butanol, pentanol, and octanol on unitary currents passing through N-methyl-D-aspartate (NMDA) ion channels have been studied in cultured CA1 hippocampal neurons. The cell-attached patch clamp method, with L-homocysteic acid included in the patch pipette, was used to record single channel NMDA currents at the cell resting potential or for hyperpolarizing patch potentials. With the n-alkanols added to the bath solution, the mean open times for the NMDA channel were diminished and the channel conductance was unchanged. A decrease in mean open time to about 70% of control value was found with butanol (3 mM), pentanol (1 mM), and octanol (0.02 mM). In addition the n-alkanols had small effects to decrease the frequency of channel openings and to increase the amplitude of the unitary currents. The effects of the alcohols on intracellular calcium levels, during NMDA applications, were also measured using the fluorescent dye FURA II.