The Increased Expression Of Activated GABA Receptors Within The Arcuate Nucleusis Associated With High Intraocular Pressure

Purpose To assess the expression and function of activated gamma-aminobutyric acid(GABA)receptors within the arcuate nucleus(ARC)in different high intraocular pressure animal models.Methods Immunofluorescence and immunohistochemical staining were used to assess the expression of activated GABA-A/B receptors within the ARC of three different models: 10-month old DBA /2J mice,acute high intraocular pressure mouse model(untreated C57 mice served as control),and chronic high intraocular pressure rat model(untreated and sham-operated SD rats served as control)Furthermore,antagonists of the GABA-A/B receptors were separately injected into the ARC of the chronic models.Then,the retina was removed and stained with hematoxylin and eosin,and the ganglion cells were counted.Intraocular pressure(IOP)of the antagonist-injected group was also recorded.The chronic models and the saline-injected group served as control.Results The expression of activated GABA-A/B receptors within the ARC was markedly higher in DBA/2J than in normal mice(P < 0.05).In acute high intraocular pressure mouse models,the expression of activated GABA-A/B receptors within the ARC was higher than in normal mice at 24 h,48 h,and 72 h(P < 0.01).In chronic models,the same trend of increased GABA-A/B receptor levels was observed in the ARC.Moreover in chronic models,treating with GABA-A/B receptor antagonists in the ARC decreased IOP and reversed retinal ganglion cell apoptosis(both P < 0.05).Conclusions Increased IOP induces activation of GABA-A/B receptors in the ARC.GABA-A/B receptor activation may be involved in IOP regulation.