Miniature end plate currents recorded from Pagothenia borchgrevinki muscle at different temperatures and measurements of the function of the oculomotor (eye movement response) control system

Miniature end plate currents (MEPC) were recorded from fish muscle of Pagothenia borchgrevinki to test the hypothesis that the high proportion of unsaturated lipids will result in increased membrane fluidity and more rapid decay of synaptic electrial events, due to faster closing of membrane ion gates. MEPCs from 9 preparations of Pagothenia borchgrevinki extraocular muscle (inferior oblique) were recorded over a temperature range of 0°C to 20°C. The frequency response and speed of action of eye muscles in Antarctic fish was measured to assess the function of the oculomotor control system in fishes adapted to extreme cold. Eye movement was monitored with an optoelectronic movement detector. For the eye movement experiment, the brain was removed and the spinal cord destroyed in an otherwise intact fish. The sixth cranial nerve was stimulated by constant frequency pulse trains and movement of the eye was monitored. Eye movement, as well as swimming speeds and fin movements, were also recorded on video tape and measurements of speed and amplitude of naturally occurring rapid eye movement were made from the tapes to compare with the physiological data.