Effects of cefazolin and cefoperazone on glutamate transporter 1 isoforms and cystine/glutamate exchanger as well as alcohol drinking behavior in male alcohol-preferring rats

Abstract

Previously, we have reported that cefazolin and cefoperazone treatments attenuated ethanol consumption, at least in part, through upregulation of GLT-1 expression in male alcohol-preferring (P) rats. In this study, we determined the effects of these compounds on the expression of GLT-1 isoforms (GLT-1a and GLT-1b), cysteine/glutamate exchanger (xCT), which is another glial glutamate transporter co-localized with GLT-1, and glutamate/aspartate transporter (GLAST). We found that cefazolin and cefoperazone treatments decreased ethanol intake and upregulated both GLT-1 isoforms, GLT-1a and GLT-1b, in nucleus accumbens (NAc) and prefrontal cortex (PFC) compared to saline treated group. In addition, cefazolin increased the expression of xCT in NAc and PFC, while cefoperazone upregulated xCT expression only in NAc. However, we did not find any significant differences in GLAST expression between the treated and control groups. Overall, our findings suggest that cefazolin and cefoperazone may be considered as potential compounds for the treatment of ethanol dependence.

Keywords: Alcohol intake; GLAST; GLT-1a; GLT-1b; Glutamate; xCT.

Figure 1

Changes in ethanol and water intake following treatment of cefazolin and cefoperazone in male P rats exposed to five weeks of free choice of water and ethanol. A) Effects of cefazolin and cefoperazone treatments on ethanol intake (g/kg/day). B) Effects of cefazolin and cefoperazone treatments on water intake (g/kg/day). Data are represented as mean ± SEM; (**p < 0.01; #p < 0.001), (n = 6 for each group).

Figure 2

Changes in GLT-1a expression in NAc and PFC following treatment with cefazolin and cefoperazone in male P rats. A) Immunoblots for GLT-1a and control loading protein (GAPDH) expression in NAc. B) Immunoblots for GLT-1a and control loading protein (GAPDH) expression in PFC. C) Quantitative t-test analysis of immunoblots revealed a significant increase in GLT-1a/GAPDH ratio in NAc in cefazolin- and cefoperazone-treated groups compared with saline-treated group (control value is 100%). D) Quantitative t-test analysis of immunoblots revealed a significant increase in GLT-1a/GAPDH ratio in PFC in cefazolin- and cefoperazone- treated groups compared with saline-treated group (control value is 100%). Data are expressed as mean ± SEM. (*p<0.05). (n=6 for each group)

Figure 3

GLT-1b expression following treatment of cefazolin and cefoperazone in NAc and PFC. A) Immunoblots for GLT-1b and control loading protein (GAPDH) expression in NAc. B) Immunoblots for GLT-1b and control loading protein (GAPDH) expression in PFC. C) Quantitative t-test analysis of immunoblots revealed a significant increase in GLT-1b/GAPDH ratio in NAc in cefazolin- and cefoperazone-treated groups compared with saline-treated group (control value is 100%). D) Quantitative t-test analysis of immunoblots revealed a significant increase in GLT-1b/GAPDH ratio in PFC in cefazolin- and cefoperazone-treated groups compared with saline-treated group (control value is 100%). Data are expressed as mean ± SEM. (*p<0.05). (n=6 for each group)

Figure 4

xCT expression in NAc and PFC following treatment with cefazolin and cefoperazone. A) Immunoblots for xCT and control loading protein (GAPDH) expression in NAc. B) Immunoblots for xCT and control loading protein (GAPDH) expression in PFC. C) Quantitative t-test analysis of immunoblots revealed a significant increase in xCT/GAPDH ratio in NAc in cefazolin- and cefoperazone-treated groups compared with saline-treated group (control value is 100%). D) Quantitative t-test analysis of immunoblots revealed a significant increase in xCT/GAPDH ratio in PFC in cefazolin-treated group and not significant in cefoperazone-treated group compared with saline-treated group (control value is 100%). Data are expressed as mean ± SEM. (*p<0.05). (n=6 for each group)

Figure 5

GLAST expression following treatment with cefazolin and cefoperazone in NAc and PFC. A) Immunoblots for GLAST and control loading protein (GAPDH) expression in NAc. B) Immunoblots for GLAST and control loading protein (GAPDH) expression in PFC. C) Quantitative t-test analysis of immunoblots revealed a non-significant increase in GLAST/GAPDH ratio in NAc in cefazolin- and cefoperazone-treated groups compared with saline-treated group (control value is 100%). D) Quantitative t-test analysis of immunoblots revealed a non-significant increase in GLAST/GAPDH ratio in PFC in cefazolin- and cefoperazone-treated groups compared with saline-treated group (control value is 100%). Data are expressed as mean ± SEM. (n=6 for each group)