| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1998: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
The reverse transcriptase-polymerase chain reaction was used. After rats had been restrained for 10-240 min, 30- and 60-min stress resulted in a significant fall in the level of α1 adrenoceptor mRNA in the hypothalamus, while significant elevation was noted after 60-, 120- and 240-min stress in the midbrain. When rats had been restrained for 4 h or 4 h per day for 2 or 3 consecutive days, 3-day stress resulted in a significant decrease in the level of α1 adrenoceptor mRNA, whereas single stress did not significantly affect it in the hypothalamus. In the midbrain, the level significantly increased after a single stress, but significantly decreased after repeated stress. The regional differences may be due to involvement of hypothalamic-pituitary-adrenal axis. The exact mechanism of the observed fall in the both regions after repeated stress is not clear and no previous studies have demonstrated such findings. On the expression of interleukin-6 (IL-6) and IL-6 receptor (IL-6R) mRNAs, single stress did not significantly affect the expression of IL-6 mRNA but significantly reduced the level of IL-6R mRNA, while 2- and 3- day stress significantly reduced the both levels in the hypothalamus. In the midbrain, single stress resulted in a significant rise in the level of IL-6 mRNA, and a significant fall in the level of IL-6R mRNA. Two day stress did not significantly affect the both levels but significantly reduced the both levels in the same region. IL-6 might be suppressed by hypothalamic-pituitary-adrenal axis. We cannot as yet explain the mechanism for observed findings on the repeated stress. We are investigating the effects of stress on the opioid receptor subtypes and the effects of agonists and antagonists of opioid and adrenergic receptor subtypes on IL-6 and IL-6R mRNA.
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