Distribution and quantitative detection of GABA A receptor in Carassius auratus gibelio

Gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in brain, is synthesized from glutamate and metabolized to succinic semialdehyde by glutamic acid decarboxylase (GAD) and GABA transaminase (GABA-T), respectively. The fast inhibitory effect of GABA is mediated by GABA type A (GABA A ) receptors that are associated with several neurological disorders, and GABA A receptors are targets of several therapeutic agents. To date, information on the distribution and quantity of GABA A receptors in Carassius auratus gibelio is still limited. We investigated for the first time, the tissue-specific distribution of GABA A Rβ2a and GABA A Rβ2b, the two subunits of the predominant GABA A receptor subtype (α1β2γ2), and then, the expression of GABA A Rβ2a, GABA A Rβ2b, GAD, and quantified GABA-T genes in different tissues by quantitative real-time PCR method and compared different expressions between two developmental stages of C . auratus gibelio . Results showed that GABA A Rβ2a and GABA A Rβ2b genes expressed in both brain and peripheral organs using reverse transcription-polymerase chain reaction. In addition, the majority of GABA A Rβ2a, GABA A Rβ2b, GAD, and GABA-T were mainly synthesized in brain; however, a considerable amount of GABA-T was secreted from the peripheral tissues, especially in the liver. Moreover, the expression of GABA A Rβ2a and GABA A Rβ2b genes in different tissues varied with body weight change. This study provides a reference for further studies on GABA and GABA A receptors subunits and an insight on the possible pharmacological properties of the GABA A receptor in C . auratus gibelio .