A Study On The Expression Of Dopamine D1 Receptor's After Brain Concussion In Rats

Objective: To observe the changes of dopamine receptor' s expression after concussion of the brain in rat. Methods: The brain concussion models in rats were reproduced by a metallic pendulum-striker device. 48 rats were randomly divided into 6 injury groups (n=8 in each group) of Id, 2d, 4d, 8d, 16d and 24d after injury, and other 8 normal rats served as control group. Each specimen labeled by rabbit anti~Dl polyclonal antibody (1:100) was stained using S-P staining of immunohistochemistry. The intensity of the positive Dl-immunoreactive neurofibers of hippocamp (CA1 CA2 CA3) was qualitatively analyzed by light microscope . The positive reaction of D1(dopamine receptor)neuron in the prefrontal cortex , parietal cortex, medial septal nucleus (MSN), vertical of diagonal band nucleus of Broca (VDB) and thalamencephalon was quantitatively analyzed by image analysis system .Results: 1. The expression of Dl in the neuron cells and neurofibers of the prefrontal cortex decreased from the first day to the 4th day after injury , and recovered increasingly during later , and recovered normal till the 24th day. The expression of Dl in parietal cortex and CA1 of the hippocamp decreased from the 1st day to the 4~thday, and recovered from the 8th day to the 16th day, but still subnormal in some sort till the 24th day. The expression of Dl in CA2 and CA3 decreased from the 1st day to the 2~nd day, and recovered from the 4~nd day, and till the 24th day recovered normal. The expression of dopaminereceptor D1 in neuron cells of VDB decreased during the 1st day to the 8th day after injury and increased during the period of the 16th day to the 24th day, but that was still lower than normal control. The expression Dl receptor decreased during the 1st day to the 4th day and increased during the8lh day to the 24th days in RT . That decreased during the 1st day to the 16th day and increased to the 24th day in MSN. The expression of Dl receptor has not statistical difference in these region. Conclusions: l.The model of brain concussion in rats can be established successfully using iron pendulum hitting device; 2. The dopamine receptor' s expressions in the neuron cells and the neurofibers in prefrontal cortex, parietal cortex and hippocamp were existed. Those expressions had changes in different degrees but there was no significant difference. 3. In the regions of RT% VDB and MSN , the different changes of the positive expression of Dl receptor were observed, but still had no statistical difference.