Günün zamanı ve pineal bez'in wistar albino ratlarda anksiyete benzeri davranışlar ve öğrenme performansı üzerine olan etkileri

The previous studies on the anxiety like behavior in rats by using elevated plus maze and open field have provided rather unequivocal results since they obtained data at different times of the day. These studies have never investigated the effects of the different times of day in a single research paradigm even though the results of such studies are generally attributed to the different measurement times. Thus, we aimed to examine the effects of the time of the day and the pinealectomy on anxiety like behavior in male Wistar albino rats by using elevated plus maze and open field in the first study. Experiments were performed with control and pinealectomy groups at the four different time points (06:00, 12:00, 18:00 and 24:00 hours; LD 12:12, lights on at 0600 and off at 1800). In open field, the main effect of the measurement time was significant on the total distance travelled, the mobility and the velocity. In elevated plus maze, the main effect of the measurement time was significant on the total distance travelled, the total entry to closed arms, and mobility. In the second study, we examined the effects of pinealectomy, constant release melatonin implants and timed melatonin injections on spatial memory in male Wistar rats by using Morris water maze. Pinealectomy, melatonin injection and melatonin implantation groups were performed including controls for all groups. After a week of the pinealectomy and melatonin implantation surgeries, we applied the injections and made the training trials throughout four days. At the fifth day, experiments were performed and recorded. Spatial memory performance of the rats was impaired by the pinealectomy and melatonin injections since they elongated the latency and shortened the time passed in the correct quadrant. Melatonin implantation did not affect the spatial memory performance of the rats. The latency and the time passed in correct quadrant were not statistically different from their controls. Beside the contribution of these results obtained from these two studies to the behavioural science, these results were also important for representing a procedural mistake in the previous studies.