OPTICAL CHANGES IN UNMYELINATED NERVE DURING AND AFTER ABNORMAL ELECTROGENESIS

Publisher Summary This chapter discusses the optical changes in unmyelinated nerve during and after abnormal electrogenesis. During the past decade, various optical techniques were successfully applied to studies on membrane macromolecular motion during excitation of axons or whole nerves. Induced fluorescence, birefringence, and light scattering transient changes during normal nerve or isolated axon responses have been recorded. The chapter discusses a study to examine optical changes, mainly birefringence changes, of the crab unmyelinated nerve during and after abnormal response elicited either by convulsant treatment (PTZ, TEA), by repetitive (tetanic) stimulation or by the application of strong electroshocks of reversible action. Crab nerves, isolated from legs or claws of the mediterranean crab Caroinus maenas , were equilibrated for few minutes in normal sea water. Action potential was recorded under air gap conditions. Nerve optical changes were measured by positioning the nerve on the stage of a polarizing microscope, with long axis at a 45° angle from the polarizer and analyzer crossed.