The Effect On GABA-AR Alpha1 Subunit Of Spinal Cord After Intrathecal Injection Of Bupivacaine In Rats

Objective To investigate the influence about the γ- aminobutyric acid GABA-ARα1 subunit expression after we inject the medicine bupivacaine on the mice’s spinal cord lumbar enlargement. Discussing the mechanism about the sedation function when we gave the intrathecal injection. Methods we prepared 32 male SD rats and their weight is between 260-280 g. All of them were randomly divided into four groups: the blank control group(group C), saline control group(NC), 0.5% bupivacaine 10 min group(B10 group), 0.5% 30 min bupivacaine group(B30 group). We will do nothing treatment measures on the group C. Finding the same material as the next group: After the rest of three groups were established the rat model of subarachnoid catheter, we will give the saline injection or 0.5% bupivacaine 20 ul, Finding the Lumbar enlargement of spinal cord from the the corresponding point on the cervical spine which is cutted off. Then we will do the Nissl staining, immunofluorescence staining. And watch the morphology of spinal cord nerve cells, the GABA-ARα1 protein’s distribution in the spinal and the average optical density change on the spinal II Plate layer;Making use of the method of western-blot to check the change about the GABA-ARα1 Subunit protein which is put into the total protein, Cytoplasmic protein and Cell membrane protein.Results 1. Nissl staining, we can see all groups of never cells clearly which were stay in order, the structure of nucleus is fairly clearly, and no morphological changes. 2. Immunofluorescence result showed that: Spinal lamina II among all the groups the GABA-ARα1’s average optical density is no any change.(p>0.05) 3. Western-blot test results showed that: GABA-AR alpha 1 subunit expression in all groups include B10 group, B30 group,C group and NC group were decreased sharply.(p<0.01),and B10 group is more obiviously. The GABAAR alpha 1 subunit expression in all groups of Cell membrane protein: B10 group,B30 group, the C group and NC group, is increased more obiviously.(p<0.01),and B10 group is increased more obiviously. Conclusion:Giving injection the 0.5% bupivacaine into the subarachnoid can make the GABA-AR alpha 1 subunit protein transfer to the Cell membrane from the Cytoplasm, The expression of the number of the cell membrane receptor was raised, maybe it is the one of the Mechanisms which cause the Spinal block induced sedation. After injecting 0.5% bupivacaine into the Subarachnoid for ten minutes which can give greatest influence on the GABA-AR alpha 1 subunit protein in the cell membrane surface. Conclusion clinically relevant concentrations in rats by intrathecal injection of bupivacaine within 30 min total protein subunit expression GABAARα1 no significant change, while the cytoplasm GABAARα1 subunit downregulation, upregulation of cell membranes GABAARα1 subunit, suggesting GABAARα1 subunit rapid transport protein from the cytoplasm to the cell membrane, increasing the number of membrane expression, resulting in sedation.