Abstract:

Objective   To explore mechanisms of dopamine(DA) inducing GH4 cell apoptosis and glutathione(GSH)protecting GH4 cells from apoptosis induced by DA. Methods   ① GH4 pituitary cells were treated with DA at 0, 100, 300 and 500μmol/L for 24h, then treated with DA at 500μmol/L for 0,1,3,5,12 and 24h to select the appropriate concentration and time. ② Then GH4 cells were treated with raclopride(a D2 receptor antagonist, Rac)and GSH to explore the effects of Rac and GSH on apoptosis.  ③Apoptotic cells were counted by an inverted phase contrast microscope. Morphological appearance was observed by PI labeling, and expressions of Bcl-2 and PARP-1 were detected by Western blot. Results   DA induced concentration-and time-dependent GH4 cell apoptosis. A selective D2 receptor antagonist could not block the cytotoxic effect. PI revealed that exposure to GSH (1mmol/L) for 1h prior to the DA treatment attenuated DA-induced apoptosis. Western blot showed up-regulation of Bcl-2 and down-regulation of PARP-1. Conclusion   DA exerts cytotoxic effects on GH4 cells mainly through auto-oxidation in the intracellular space. A selective D2 receptor antagonist cannot block DA-induced apoptosis, while GSH can block it, which may be relevant to regulation of Bcl-2 and PARP-1.

Key words: Dopamine； GH4 cells； Apoptosis； Glutathione；  Genes, bcl-2; Genes, PARP-1