Electrophysiological neuromethodologies

Abstract

Neurotoxic chemicals can alter neuronal excitability and disrupt synaptic transmission in the central nervous system to induce a variety of neurological disorders. These neurotoxic effects can be assessed with high sensitivity and in functional tissue and real time by using electrophysiological recording techniques in freshly isolated brain slices, typically in rats or mice. This provides far greater sensitivity than neurochemical measures of neurotransmission and permits assessment of function of both pre- and postsynaptic elements of the synapse, from the same slice. Preparation of brain slices from adult rodents has been a challenge due to poor viability of the tissue post-slicing. This has dramatically hampered use of these techniques in experimental paradigms in which neurophysiologic effects of toxic chemicals can be assessed during chronic exposure of animals over their life span. This chapter presents a simplified method for preparing brain slices from adult animals. It applies voltage- and current-clamp recordings in slices of the brainstem and cerebellum, two brain regions vital to motor function, for which neurotoxic chemicals have been shown to act. However with slight modifications, the principles could be applied to other brain regions such as hippocampus or corpus striatum to study effects of neurotoxic chemicals on central nervous system synaptic function.