Ethanol Stimulates Endoplasmic Reticulum Inositol Triphosphate and Sigma Receptors to Promote Withdrawal-Associated Loss of Neuron-Specific Nuclear Protein/Fox-3.
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ABSTRACT: BACKGROUND:Prior studies demonstrate that ethanol (EtOH) exposure induces the release of intracellular calcium (CA(2+) ) in modulation of ?-aminobutyric acid-ergic tone and produces concomitant alterations in sigma (?)-1 protein expression that may contribute to the development EtOH dependence. However, the influence of CA(2+) released from endoplasmic reticulum (ER)-bound inositol triphosphate (IP3) and ?-1 receptors in regulating hippocampal function has yet to be delineated. METHODS:Rat hippocampal explants were subjected to chronic intermittent EtOH (CIE) exposure with or without the addition of IP3 inhibitor xestospongin C (0 to 0.5 ?M) or ?-1 receptor antagonist BD-1047 (0 to 80 ?M). Hippocampal viability was assessed via immunohistochemical labeling of neuron-specific nuclear protein (NeuN)/Fox-3 in CA1, CA3, and dentate gyrus (DG) subregions. RESULTS:Exposure to CIE produced consistent and significant decreases of NeuN/Fox-3 in each primary cell layer of the hippocampal formation. Co-exposure to xestospongin reversed these effects in the CA1 subregion and significantly attenuated these effects in the CA3 and DG regions. Xestospongin application also significantly increased NeuN/Fox-3 immunofluorescence in EtOH-naïve hippocampi. Co-exposure to 20 ?M BD-1047 also reversed the loss of NeuN/Fox-3 during CIE exposure in each hippocampal cell layer, whereas exposure to 80 ?M BD-1047 did not alter NeuN/Fox-3 in EtOH-treated hippocampi. By contrast, 80 ?M BD-1047 application significantly increased NeuN/Fox-3 immunofluorescence in EtOH-naïve hippocampi in each subregion. CONCLUSIONS:These data suggest that EtOH stimulates ER IP3 and ?-1 receptors to promote hippocampal loss of NeuN/Fox-3 during CIE.
SUBMITTER: Reynolds AR
PROVIDER: S-EPMC6662182 | biostudies-literature | 2016 Jul
REPOSITORIES: biostudies-literature
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