The assessment of neurotoxicity using the cockroach nerve cord.

The acute central nervous system toxicity of chemicals may be detected and analysed with relative ease in the isolated abdominal ventral nerve cord of the American cockroach. Stable electrophysiological measurements of axonal and both inhibitory and excitatory synaptic transmission can be made for several hours with extracellular electrodes using a mannitol-gap technique. Dose-response curves can be obtained for the effects of the chemicals. These can be analysed in terms of site of action, be it on the axons, the presynaptic nerve terminal, the postsynaptic receptors or the termination of neurotransmitter action. Possible non-specific sites are also considered.