ABSTRACT
The radial nerve cord of the ophiuroid Ophiura ophiura was subjected to immunocytochemical investigations using antibodies raised against ?-aminobutyric acid (GABA), a classical inhibitory neurotransmitter found in both vertebrate and invertebrate nervous systems. The GABA containing neurons were visualized on both whole mounts and ultrathin sections by using secondary labels: fluorescein isothianate-labelled donkey anti-rabbit IgG and protein A-gold conjugate, respectively.
