| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
Clinical Study:
The effect of general anesthetics on the pituitary hormones (ACTH and vasopressin) responses in human was studied. It is clarified that isoflurane and sevoflurane did not attenuate the responses but nitrous oxide suppress them. The effect of benzodiadepine on the responses was studied. Midazolam, added to sevoflurane anesthesia, did not influence the responses. These results suggested that these volatile anesthetics have no effect on the stress responses but nitrous oxide has suppressive effect on the stress responses and an augmentation of GABAA action did not influence the stress responses
Animal Study:
To prove the hypothesis that nitrous oxide affects the stress response by an activation of opioid neuron in the brain, the effect of general anesthetics on the Met-enkephalin and Leu-enkephalin concentration in the cerebrospinal fluid of the rabbit was studied, but the anesthetics did not Increase these opiod concentrations. Next, the effects of general anesthetics on the stressresponse were studied by using rat laparotomy model. Laparotomy stimulation increased the plasma ACTH concentraion under isoflurane anesthesia and this response was attenuated by nitrous oxide. By immunohistochemistry, it was clarified that this stimulation also increased the expression of c-Fos in the nucleaus around the third ventricle, especially paraveritricular nucleus, and cerebral cortex from parietal to temporal lobe. However, the difference of the amount of the protein expression among the general anesthetics was still obscure. Futher study is necessary to clarify whether or not nitrous oxide suppresses the stress response through the intrinsic opioids in the brain
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