Effect of the pineal gland on 5-hydroxytryptamine and γ-aminobutyric acid secretion in the hippocampus of male rats during the summer and winter

摘要

ObjectiveThe present study aimed to investigate the effect of seasonal variation on neurotransmitter release in the hippocampus of normal rats and rats with pineal excision.MethodsTwo time points, the summer and winter solstice, which are the longest and shortest days of the year, respectively, were selected. Male Sprague–Dawley rats that underwent a sham operation without pineal excision were included as a control group. The concentrations of 5-hydroxytryptamine (5-HT) and γ-aminobutyric acid (GABA) were determined by radioimmunoassays and enzyme-linked immunosorbent assays, respectively.ResultsIn the winter, the 5-HT and GABA levels in normal rats exhibited a significant difference compared with those in the operation group (P?