Gamma-aminobutyric acid induces feeding behaviour in the marine mollusc, Clione limacina.

The effects of gamma-aminobutyric acid (GABA) on the behaviour of the marine pteropod mollusc Clione limacina were studied. In intact molluscs, injection of GABA evoked the consummatory stage of feeding behaviour, i.e. protracting the tentacles, opening the mouth, catching and swallowing prey, as well as some acceleration of locomotion. In the isolated CNS, GABA (10(-5)-10(-4) M) strongly activated the feeding rhythm generator, excited the cerebral motoneurons innervating tentacle muscles (TenMNs), and accelerated locomotor rhythm. A direct excitatory action of GABA (10(-8) M) upon TenMNs was demonstrated on isolated cells extracted from cerebral ganglia. It is concluded that GABA plays an important role in activation of various neuronal networks (organization of 'functional synergy') responsible for the consummatory stage of feeding behaviour.