Effect of Alpha-2 Receptor Blocker on Serotonin Release in Rat Hippocampal Slices / 대한남성과학회지

ABSTRACT

PURPOSE: It is known that alpha-2 receptor is found at the presynaptic serotonergic nervous system and a consequence of increased activation of alpha-2 receptor decreases the serotonin release. So Alpha-2 blockers may have the effect on the release of serotonin. The major serotonergic innervation is found at the hippocampus. This study was performed to investigate the effect of the alpha-2 receptor blocker to serotonin release in rat hippocampus. MATERIALS AND METHODS: The hippocampus from the male rat brain was sliced. After 30 minutes preincubation in the normal buffer, the slices were incubated for 20 minutes in a buffer containing 0.1 microM[3H]5-HT for uptake, and washed. After administration of alpha 2 receptor blockers, yohimbine (10-5M), the release of [3H]5-HT into the buffer was measured, the radioactivities in each buffer and the tissue were counted and the results were expressed as a percentage of the total activity. The value of released [3H]5-HT was expressed as percent of the value at 50 minutes when a steady state of [3H]5-HT release was obtained. RESULTS: After adminstration of yohimbine (10-5M), the values(mean+/-SE, %) were 147.5+/-9.2 at 60 minutes and 143.8+/-7.3 at 70 minutes compared to the values of control group, 96.6+/-1.9 at 60 minutes and 89.6+/-2.3 at 70 minutes. The release was increased significantly after adminstration of yohimbine. CONCLUSIONS: Alpha-2 receptor blockers increased the release of serotonin. It is suggested that the consideration of the increase of serotonin release by alpha-2 receptor blockers may be helpful to understand the effect of serotonin on sexual function.