Reaction of Microglia and Neurons of the Hippocampal CA1 Field to Chloral Hydrate in Old Rats

We studied the effect of chloral hydrate on the reaction of microglia and neurons of the hippocampal CA1 field in old Wistar rats. According to the results of morphological and immunohistochemical analysis, chloral hydrate at a dose of 400 mg/kg does not lead to a decrease in the population of neurons in the stratum pyramidale in the hippocampal CA1 field in rats aged 24 months after 48 h. The reaction of microglia is registered as an increase in immunoreactivity to Iba1 and morphological transformations of microgliocytes without a considerable change in their number in the stratum oriens, stratum pyramidale, and stratum radiatum of the hippocampal CA1 as compared to non-anesthetized animals. Microglia activation following anesthesia with chloral hydrate may underlie the earlier shown cognitive impairment in aged rats.