Chipkin R E, Latranyi M B
Brain Res. 1984 Jun 11;303(1):1-6. doi: 10.1016/0006-8993(84)90204-x.
Spontaneously hypertensive (SH), Wistar Kyoto (WKY) or Sprague-Dawley (SD) rats were tested for their responsiveness to noxious mechanical pressure before and after a subplantar yeast injection to the right rear paw. Prior to the yeast injection, hypertensive animals were less responsive to pain relative to normotensive animals, as seen in the significantly greater pre-yeast latencies of SH compared to WKY or SD rats. Subplantar yeast injection produced hyperreactivity in the inflamed paws of WKY or SD rats, with no effect on the contralateral non-injected paw. However, identical subplantar yeast injections to hypertensive animals produced a robust, long-lasting antinociceptive effect in both rear paws of SH rats. This effect was not reversed by naloxone (opiate antagonist), labetalol (beta-blocker/vasodilator antihypertensive), or hydralazine (peripheral vasodilator antihypertensive); the antinociception was not potentiated by thiorphan (enkephalinase inhibitor). However, the alpha 2-receptor antagonist yohimbine (0.1-5 mg/kg s.c.), produced a dose-related reversal of the yeast-induced antinociception in SH rats. These results suggest that the subplantar yeast injection is triggering descending noradrenergic pain inhibitory pathways in SH rats.
对自发性高血压（SH）大鼠、Wistar Kyoto（WKY）大鼠或Sprague-Dawley（SD）大鼠进行右后足底酵母注射前后对有害机械压力的反应性测试。在酵母注射前，与正常血压动物相比，高血压动物对疼痛的反应性较低，如SH大鼠在酵母注射前的潜伏期明显长于WKY或SD大鼠。足底酵母注射使WKY或SD大鼠发炎的爪子产生高反应性，对侧未注射的爪子无影响。然而，对高血压动物进行相同的足底酵母注射，在SH大鼠的双后爪中产生了强烈、持久的抗伤害感受作用。这种作用不会被纳洛酮（阿片拮抗剂）、拉贝洛尔（β受体阻滞剂/血管扩张剂类抗高血压药）或肼屈嗪（外周血管扩张剂类抗高血压药）逆转；硫喷妥（脑啡肽酶抑制剂）也不会增强这种抗伤害感受作用。然而，α2受体拮抗剂育亨宾（0.1 - 5毫克/千克皮下注射）可使SH大鼠中酵母诱导的抗伤害感受作用产生剂量相关的逆转。这些结果表明，足底酵母注射正在触发SH大鼠下行去甲肾上腺素能疼痛抑制通路。
