A modification of the glyoxylic acid induced histofluorescence technique for demonstration of catecholamines and serotonin in tissues of Aplysia californica.

A modified glyoxylic acid technique was used to examine central and peripheral nervous tissues in Aplysia californica. In addition to confirming the distribution of catecholamines and serotonin in the central nervous system, the method demonstrated the presence of monoamines in the opaline gland and bag cell clusters where they may act as transmitters. In conjunction with electrophysiological techniques this method may be useful to identify other monoamine-containing neurons in Aplysia.