The Effect Of Opioid Peptide On Gastric Mucosa Injury Induced By Restraint Water-immersion Stress In Rat

Studies from our laboratory have previously shown that the gastric mucosa injury of rat were induced by restraint water-immersion stress (RWIS), and the neuronal activation were enhaneced in hypothalamic supraoptic nucleus (SON), paraventricular nucleus (PVN), the medulla dorsal vagal complex vagus complexes (DVC) .Using the immediate early gene c-fos as a marker of activated neurons have demonstrated significant neuronal activation in this region under the RWIS. In these activated neurons, there are arginine vasopressin (AVP) neurons, oxytocin (OT) neurons, norepinephrine (NE) neurons, and cholinergic neurons (ACh).But, this is only a part of nervous that take part in the response. Little is known about the kind of another neurons. Previous research showed that methionine-enkephalin (M-ENK) immunopositive soma and axon terminals was found in hypothalamus, diencephalon, brainstem and spinal cord and that M-ENK can coexist with AVP,OT in the neurons of hypothalamus SON,PVN. Met-enkephalin analog injected intraperitoneally to rats at doses of 5-20 mg/kg respectively showed a protective effect on gastric lesion induced by cold-restraint stress. In addition, M-ENK played an important regulation role in neuroendocrine activity. Therefore, by M-ENK+Fos immunohistochemistry double-labeled techniques and the technique of intracerebroventricular injection, we will begin the working of inquiry focused around the response of M-ENK neurous and the role of M-ENK on gastric mucosa injury of rat in RWIS.The research was divided into four parts:Part one, the influence of colchicine pretreatment to M-ENK expression in central nervous system of the RWIS rat. We pretreated the rats with 1mg/kg colchicine and normal saline injection in abdominal cavity respectively, and 100μg/kg colchicine in lateral ventricle to observe the influence of different processing method to the structural display of M-ENK immunohistochemical positive. The result showed that injection in abdominal cavity and lateral ventricle had the similar effects with displaying the obvious pericaryon, while the control group not. Thereout, we choose the simple and convenient Intraperitoneal Injection method to carry on the follow-up testing.Part two,the influence of RWIS on the M-ENK expression of rats'central neurons. Using immunohistochemistry single-labeled and double-labeled techniques to find M-ENK positive expression in SON, PVN of hypothalamus, the DVC. The result shows that, there is obvious M-ENK immune positive reaction in DMV, NTS, NA, but compared with the control group, there is no significant differences(P>0.05); whether the single-labeled of M-ENK immunoreaction or the double-labeled of M-ENK and Fos immunoreaction, there is no positive soma in SON and PVN. RWIS 1h doesn't have significant effect on the M-ENK expression and neurons'activities in hypothalamus, medulla. There are lots of M-ENK nerve endings in corpus striatum, there is no significant differences(P>0.05)between the experimental group and control group.Part three, the role of M-ENK in central nervous system on RWIS induced gastric mucosa injury of rat. By ICV trace injection enkephalin into paracele in RWIS induced gastric mucosa injury. We studied the role of M-ENK in RWIS. The results were as follows: there was gastric mucosa injury index of rat no significant difference (P﹥0.05) between the group of injection M-ENK and the control group.Part four, the effects of RWIS on pineal body, thyroid, pancreatic island and adrenal in rat were explored. The c-Fos expression in the main endocrine glands was examined by immunohistochemical technique. Results: Compared with the control group (RWIS 0h), the number of c-Fos positive cells and integrated optical density (IOD) in the thyroid,medulla and zona glomerulosa of adrenal increased significantly (P﹤0.05). Although pineal's Fos expression was obvious in each group, there were no prominent differences (P﹥0.05) between the two groups. No Fos expression was discovered in the zona reticularis of adrenal cortex, pancreatic island in each group. These results suggest that the thyroid, zona glomerulosa and medulla of adrenal participate in the response to the RWIS. To sum up, at the observation of hypothalamus and medulla oblongata, M-ENK immunohistochemical Positive perikaryon was only found in the NTS, DMV as well as NA have M-ENK nerve endings; we have not found any positive perikaryon or nerve endings in PVN or SON of the hypothalamus; a large number of M-ENK nerve endings were found in striatum.The activity of the M-ENK neurons, which were in DMV, NTS and NA of the medulla as well as in nerve center ,was not obvious relation with gastric mucosal injury caused by RWIS,and the activity of the main endocrine gland.