低盐胁迫下三疣梭子蟹γ-氨基丁酸及其A型受体相关蛋白对渗透压调节的影响

Effects of gamma-aminobutyric acid and GABA_A receptor associated protein on osmotic regulation in Portunus trituberculatus under low salinity stress

为探究低盐胁迫下γ-氨基丁酸(GABA)及其A型受体相关蛋白(GABARAP)在三疣梭子蟹渗透压调节过程中起到的作用,实验检测了低盐度10条件下,三疣梭子蟹在0, 3, 6, 9, 12, 24, 36,48 h的血清渗透压、血清氯离子(Cl-)浓度等指标,同时对鳃组织的GABA量以及GABARAP基因表达量变化进行测定.结果显示,血清渗透压和血清Cl-浓度在12 h内显著下降(P<0.05), 12 h后趋于稳定;相对0 h,血清Cl-浓度降低17.93%,血清渗透压降低24.46%,与外界海水渗透压的差值维持在(183.21±9.51)mOsm·kg^(-1). GABA量及GABARAP基因表达量波动上升, 12 h后基本维持稳定.研究结果表明,三疣梭子蟹对低盐度条件的适应性调节在12 h内进行,之后基本维持稳定,GABA量以及GABARAP基因表达量在此过程中呈现显著的正相关关系,对血清Cl-浓度的调节起到了重要作用,使得12 h后血清渗透压与外界海水渗透压维持在(183.21±9.51)mOsm·kg^(-1),保证各项生理活动的正常进行.

In order to investigate the effects of gamma-aminobutyric acid (GABA) and GABAA receptor associated protein (GABARAP) on osmotic regulation in Portunus trituberculatus under low salinity stress, the osmotic pressure and concentration of chloride ion (Cl^-) in the serum of P. trituberculatus at 0, 3, 6, 9, 12, 24, 36 and 48 h were measured under salinity 10, the changes of GABA content and GABARAP gene expression in gill tissue were also determined at each time point. The results showed that osmotic pressure and concentration of chloride ion (Cl^-) in the serum decreased significantly within 12 hours (P<0.05), and stabilized after 12 hours, the concentration of Cl^- decreased 17.93% and the osmotic pressure of the serum decreased 24.46% compared to time 0 h, the difference between the serum osmotic pressure and the seawater was (183.21±9.51)mOsm·kg^-1 after 12 h. The content of GABA and the gene expression of GABARAP increased at the beginning and became stable after 12 h. These results indicated that the regulation of P. trituberculatus to low salinity conditions should be completed within 12 h. GABA content and GABARAP gene expression showed a significant positive correlation during this process. The results suggest that they played an important role in the regulation of Cl^- to maintain the difference between the serum osmotic pressure and the seawater at (183.21±9.51)mOsm·kg^-1, which is of great importance for P. trituberculatus to ensure the normal physiological activities.