Abstract

Gamma-aminobutyric acid (GABA) is a neurotransmitter that is widely spread in vertebrate and invertebrate nervous systems and modulates essential physiological roles. Previous studies have reported the distribution of several neurotransmitters throughout the central nervous system (CNS) of decapod crustaceans. However, the existence and distribution of GABA in the mud crab's, Scylla olivacea, CNS has still not been reported. In this study, we investigated the distribution of GABA using immunohistochemistry. The result revealed that GABA immunoreactivity (-ir) was observed in neurons and fibres throughout the CNS, including the eyestalk, brain, and ventral nerve cord of S. olivacea. Therefore, the existence and extensive distribution pattern of GABA in the CNS of the male mud crab suggest its possible roles in feeding, locomotion, and also reproduction.