Oeltgen P R, Welborn J R, Nuchols P A, Spurrier W A, Bruce D S, Su T P
VA Medical Center, Lexington, KY.
Life Sci. 1987 Nov 2;41(18):2115-20. doi: 10.1016/0024-3205(87)90529-7.
A "Hibernation Induction Trigger" (HIT) isolated from plasma of winter-hibernating woodchucks induced hibernation in summer-active ground squirrels (Citellus tridecemlineatus). Effects of kappa opioid U69593 on the HIT-induced hibernation were examined. U69593 alone did not elicit marked behavioral alteration or hibernation in summer-active ground squirrels. U69593, however, antagonized hibernation induced by HIT in summer active ground squirrels. In the guinea pig ileum myenteric plexus-longitudinal muscle preparation, woodchuck HIT depressed the electrically-induced contraction. The depression was, however, neither reversed nor blocked by naloxone even when naloxone was used at high doses. This study demonstrates that kappa opioid, at least in the case of U69593, was unable to induce hibernation in the summer-active ground squirrels. The results also demonstrate that woodchuck HIT, like the bear HIT, did not act directly at opioid receptors. Together with our previous observation that naloxone blocked summer hibernation induced by HIT (Bruce et al., Life Sci.., this issue), it is tempting to suggest that HIT may not mediate its effects through kappa opioid receptors but may do so through other types of opioid receptors such as mu or delta. U69593 may antagonize HIT-induced hibernation as a mu or delta receptor antagonist.
从冬季冬眠的土拨鼠血浆中分离出的一种“冬眠诱导触发因子”（HIT）可使夏季活跃的地松鼠（Citellus tridecemlineatus）进入冬眠状态。研究了κ阿片类药物U69593对HIT诱导的冬眠的影响。单独使用U69593不会引起夏季活跃地松鼠明显的行为改变或冬眠。然而，U69593可拮抗夏季活跃地松鼠中由HIT诱导的冬眠。在豚鼠回肠肌间神经丛-纵肌标本中，土拨鼠HIT可抑制电诱导的收缩。然而，即使高剂量使用纳洛酮，这种抑制作用也不会被纳洛酮逆转或阻断。本研究表明，κ阿片类药物，至少就U69593而言，无法诱导夏季活跃地松鼠进入冬眠。结果还表明，土拨鼠HIT与熊HIT一样，并非直接作用于阿片受体。结合我们之前观察到纳洛酮可阻断HIT诱导的夏季冬眠（Bruce等人，《生命科学》，本期），我们不禁推测，HIT可能不是通过κ阿片受体介导其作用，而是可能通过其他类型的阿片受体，如μ或δ受体。U69593可能作为μ或δ受体拮抗剂拮抗HIT诱导的冬眠。
