Measurements of the quantal content in neuromuscular transmission of the Antarctic fish Pagothenia borchgrevinki - end plate potential recordings from muscle fibres

The Antarctic fish Pagothenia borchgrevinki was captured from near Scott Base and used to measure the quantal content in neuromuscular transmission of Antarctic fish. The amount of neurotransmitter chemical released by a nerve to stimulate a muscle is strongly temperature dependent and it was investigated whether the amount of chemical released is increased in Antarctic animals to overcome the retarding effect of the cold. The extraocular muscles were dissected and the muscle fibres were stained (some time was spent perfecting these techniques). Trains of 300-500 end plate potentials were recorded from a total of 39 muscle fibres from 17 fish over a temperature range of -2.5°C to +20°C. Measurements of muscle fibre input resistance (electrical resistance of cell membrane and contents) and space constants were also made on white muscle.