Insect blood-brain barrier: an electrophysiological investigation of its permeability to the aliphatic alcohols.

The anaesthetic effects of the aliphatic alcohols were used to measure their concentration at the neuronal surfaces of the cockroach central nervous system. The results were in most cases fairly closely described by first-order kinetics. The exchange half-times of the lower alcohols were only a few seconds, being little affected by the removal of the nerve sheath. The half-times for the higher alcohols were somewhat longer, and were more significantly reduced by desheathing; these observations were interpreted in terms of a reservoir effect resulting from their higher liposolubility. It was shown that the ionic diffusion barrier in intact nerve cords remained undamaged in the presence of the alcohols.