The Changes Of Ethology, Neuroal Intracellular Free Calcium And Morphology In Brain Regions Of Morphine-addicted Rats

Objective 1. Produced morphine-addicted rats, and to observe the changes of withdrawal signs on abstinence. 2. To observe the changes of learning-memory, felling and brain morphology in morphine-addicted rats. 3. To investigate the effects of morphine on the changes of neuroal intracellular free calcium in brain regions of rat, which will provide a theoretical foundation and technical method for clinic morphine-addicted people's therapy by Ca²⁺ antagon. 4. To evaluate the changes of morphine withdrawal syndrom and the effects of ethology,and to observe the morphological changes in brain region of morphine-addicted rats before and after stereotaxic lesion,and to explore which will provide a theoretical foundation and technical method for clinic morphine-addicted people's therapy by stereotaxic lesion.Methods 1. Produced morphine-addicted rats by morphine intraperitoneal injection with doses progressive methods. 2. 64 male Spraqui-Dawlay rats were randomly assigned to experimental or control groups. The ability of learning-memory in rats were tested with Morris water maze. Exploratory behavior in rats were observed with Open-field test. The isolation-induced aggression in rats were observed with Muricide behavior test. The morphological changes in the nucleus accumbens, hippocampus and medial prefrontal cortex in morphine-addicted rats and control groups were observed and compared under light and electron microscopy. 3. 40 male Spraqui-Dawlay rats were randomly assigned to experimental or control groups. Changes of [Ca²⁺]_i in nucleus accumbens, hippocampus and medial prefrontal cortex were detected with laser scanning confocal microscope (LSCM) by using Ca²⁺-sensitive dye fluo-3 as a calcium fluorescent probe. 4. 120 male Spraqui-Dawlay rats were divided randomly into six groups. Exploratory behavior in rats were observed with Open-field test.The isolation-induced aggression in rats were observed with Muricide behavior test.The morphological changes in the nucleus accumbens, hippocampus in morphine-addicted and lesion rats were observed and compared under light and electron microscopy. Lesion were produced by stereotaxic apparatus , electronic stimulator and Isolator.Results 1. The scores of withdrawal signs on abstinence were higher in morphine-addicted rats than that of control(P<0.05). 2. The ability of learning-memory in Morris water maze and exploratory behavior in open-field test were significant differently between two groups(P<0.05). The muricide behavior in rats were higher than that of control(P<0.05). The light and electron microscopic changes in nucleus accumbens, hippocampus and medial prefrontal cortex were found, including cellular organelle decrease, chondriosome edema, chromatin margination, karyopycnosis and necrosis. 3. [Ca²⁺]_i in the nucleus accumbens, hippocampus and medial prefrontal cortex were increased in morphine-addicted rats than that of control (P<0.05). 4. The scores of withdrawal signs on abstinence were higher than that of lesion(P<0.05). The muricide behavior in rats were higher than that of lesion (P<0.05).The light and electron microscopic changes in nucleus accumbens and hippocampus were found,including cellular organelle decrease, chondriosome edema, chromatin margination, karyopycnosis and necrosis.Conclusion 1. Morphine-addicted rats could be produced by morphine intraperitoneal injection with doses progressive methods. 2. Long-term morphine exposure can lead to damage in different brain regions and decrease exploratory behavior, but increase aggressive behavior. 3. Long-term morphine exposure can lead to damage in different brain regions and increase of neuroal [Ca²⁺]_i. 4. Long-term morphine exposure can lead to damage of neuron ultrastructure in brain. Relieve morphine withdrawal syndrom, at the same time,aggressive behavior and exploratory behavior were changed after stereotactic lesion.