Time course of SERCA 2b and calreticulin expression in purkinje neurons of ethanol-fed rats with behavioral correlates

Chronic ethanol consumption for 40 weeks in adult rats results in dilation ofthe extensive smooth endoplasmic reticulum (SER), a major component of the calciumhomeostatic system within Purkinje neuron (PN) dendrites. Aims: The aim of the present study was to determine whether chronic ethanol consumption results in alterations of the sarco/endoplasmic reticulum Ca²⁺ ATPase pump (SERCA) on theSER membrane of PN dendrites. The density of calreticulin, a calcium chaperone, was also investigated in the PN along with balancing ability. Methods: Ninety 8-month-old rats were exposed to rat chow, the AIN-93 M liquid control or ethanol diets (30/diet) for a duration of 10, 20 or 40 weeks (30/duration). Age changes relativeto the rat chow controls were assessed with 3-month-old control rats (n = 10). Balance was assessed prior to euthanasia. Quantitative immunocytochemistry was used to determine the density of SERCA 2b + dendrites and calreticulin + PN soma and nuclei. Molecular layer volumes were also determined. Results: Following 40 weeks of ethanol treatment, there were ethanol-induced decreases in SERCA 2b densities within the dendritic arbor and decreased balancing ability on the more difficult roundrod balance test. There were no ethanol-induced changes in calreticulin densities.Conclusion: It can be concluded that ethanol-induced decreases in the SERCA pump accompany SER dilation and contribute to previously reported ethanol-induced dendritic regression in PN. Ethanol-induced changes in balance also occurred. Chronic ethanol consumption does not alter calreticulin expression in PN.