Neuromuscular transmission in the frog at 31 ATA helium pressure

Synaptic potentials were recorded extracellularly in in vitro frog cutaneous pectoris nerve muscle preparation in air at 1 ATA and in a hyperbaric gas environment of 1 ATA air plus 30 ATA helium. Sufficient curare was always used in the bathing solution to prevent propagated muscle action potentials upon maximal stimulation of the nerve. Shape of the synaptic potential and poststimulus facilitation and depression were compared in these two environments. No significant differences were found.