The Effects of High Nitrogen Tensions of the Properties of Neuronal Membranes and Synaptic Transmission.
Final rept. Mar 73-May 77,
TEXAS UNIV MEDICAL BRANCH AT GALVESTON DIV OF COMPARATIVE MARINE NEUROBIOLOGY
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The effects of increased air, nitrogen andor hydrostatic pressures to 10 ATA have been studied on electrophysiological properties of identified neurons in two model neurobiological preparations, the marine mollusc Aplysia and the crayfish. Studies were done in vitro in a pressurization chamber with intracellular recordings using multiple microelectrodes in identified neurons in the Aplysia ganglion or from the crayfish giant axon. Ten ATA of air had no demonstrable effect on the resting potential, membrane resistance, time constant or action potential of neurons R2, R14 and R15 Aplysia, and equivalent pressures of nitrogen or hydrostatic force did not affect resting potential of crayfish axon. The rates of depolarization and repolarization of the crayfish axon action potential were increased significantly by nitrogen tensions to 8.6 ATA depolarization rate, 2.2 or - 0.2atm repolarization rate, 2.1 or - 0.2atm. Action potential duration was decreased 0.91 or - 0.19atm under these conditions. Hydrostatic pressure alone had an opposite effect on polarization rates.
- Anatomy and Physiology