Female rat hippocampal cell density after conditioned place preference

The hippocampus is important for learning tasks, such as conditioned place preference (CPP), which is widely used as a model for studying the reinforcing effects of drugs with dependence liability. Long-term opiate use may produce maladaptive plasticity in the brain structures involved in learning and memory, such as the hippocampus. We investigated the phenomenon of conditioning with morphine on the cell density of female rat hippocampus. Forty-eight female Wistar rats weighing on average 200-250 g were used. Rats were distributed into eight groups. Experimental groups received morphine daily (three days) at different doses (2.5, 5, 7.5 mg/kg) and the control-saline group received normal saline (1 ml/kg), and then the CPP test was performed. Three sham groups received only different doses (2.5, 5, 7.5 mg/kg) of morphine without CPP test. Forty-eight hours after behavioural testing animals were decapitated under chloroform anaesthesia and their brains were fixed, and after tissue processing, slices were stained with cresyl violet for neurons and phosphotungstic acid haematoxylin for astrocytes. The maximum response was obtained with 5 mg/kg of morphine. The density of neurons in CA1 and CA3 areas of hippocampus after injection of morphine and CPP was decreased. The number of astrocytes in different areas of hippocampus was increased after injection of morphine and CPP. It seems that the effective dose was 5 mg/kg, as it led to the CPP. We concluded that both injection of morphine and CPP can decrease the density of neurons and also increase the number of astrocytes in the rat hippocampus

Ecstasy, anxiety and rat hippocampal astrocytes

Ecstasy (MDMA) is a popular drug a used recreationally with the rave culture and consumed in a high environment temperature. Repeated and prolonged MDMA ingestion is well known to cause depression, anxiety and aggression. The aim of this study was to evaluate the sub-chronic effects of MDMA on anxiety in Wistar rats and to determine astrocytes density in the rat hippocampus after anxiety. In this study, 28 adult male Wistar rats were used. The animals were distributed randomly in four groups, one sham group (receiving 1 ml/kg 0.9% saline solution) and three experimental groups: Exp. 1 (1.25 mg/kg/day MDMA), Exp. 2 (2.5 mg/kg/day MDMA), and Exp. 3 (5 mg/kg/day MDMA). The animals received Saline or MDMA for a week (sub-chronic period). An Elevated Plus Maze apparatus was used to examine anxiety levels in the rats. 24 h. after the last injection and behavioral test, the rat brains were withdrawn and fixed with 4% paraformaldehyde, and then - after histological processing - the slices of hippocampus were stained with PTAH for astrocytes. Our results showed that MDMA at 2.5 mg/kg/day for a week was most effective in causing anxiety. We found that the number of astrocytes was increased after this period. The greatest increase in astrocyte numbers was observed in the dentate gyrus of the5 mg/kg MDMA group. We concluded that the administration of MDMA over 7 days (sub-chronic period) can cause anxiety and can have an effect on the astrocyte density of the rat hippocampus