Sakitama K
Pharmacology Section, Nippon Kayaku Co., Ltd., Tokyo, Japan.
Jpn J Pharmacol. 1993 Nov;63(3):369-76. doi: 10.1254/jjp.63.369.
The effects of centrally acting muscle relaxants on the flexor reflex mediated by group II afferent fibers (group II flexor reflex) in anesthetized intact rats and on the intrathecal noradrenaline-HCl-induced facilitation of the group II flexor reflex in anesthetized spinal rats were investigated. In anesthetized intact rats, mephenesin, tolperisone-HCl, chlorpromazine-HCl and baclofen inhibited the group II flexor reflex dose-dependently, whereas the inhibitory effect of tizanidine-HCl was bell-shaped. The effect of diazepam tended to be saturated. In anesthetized spinal rats, mephenesin, tolperisone-HCl, chlorpromazine-HCl, diazepam and baclofen also depressed the group II flexor reflex, but tizanidine-HCl slightly increased it. The intrathecal noradrenaline-HCl-induced facilitation of the group II flexor reflex was not affected by mephenesin or diazepam, but was inhibited by tizanidine-HCl, tolperisone-HCl, chlorpromazine-HCl and baclofen. These results suggest that compounds with centrally acting muscle relaxant activity depress the group II flexor reflex in different manners, and the inhibition of descending noradrenergic tonic facilitation within the spinal cord participates in the depressant action of the group II flexor reflex produced by tolperisone-HCl, tizanidine-HCl, chlorpromazine-HCl and baclofen.
研究了中枢性肌松药对麻醉的完整大鼠中由Ⅱ类传入纤维介导的屈肌反射（Ⅱ类屈肌反射）以及对麻醉的脊髓大鼠鞘内注射盐酸去甲肾上腺素诱导的Ⅱ类屈肌反射易化作用的影响。在麻醉的完整大鼠中，美芬新、盐酸托哌酮、盐酸氯丙嗪和巴氯芬剂量依赖性地抑制Ⅱ类屈肌反射，而盐酸替扎尼定的抑制作用呈钟形。地西泮的作用趋于饱和。在麻醉的脊髓大鼠中，美芬新、盐酸托哌酮、盐酸氯丙嗪、地西泮和巴氯芬也抑制Ⅱ类屈肌反射，但盐酸替扎尼定使其略有增加。鞘内注射盐酸去甲肾上腺素诱导的Ⅱ类屈肌反射易化作用不受美芬新或地西泮的影响，但受盐酸替扎尼定、盐酸托哌酮、盐酸氯丙嗪和巴氯芬的抑制。这些结果表明，具有中枢性肌松活性的化合物以不同方式抑制Ⅱ类屈肌反射，脊髓内下行去甲肾上腺素能紧张性易化作用的抑制参与了盐酸托哌酮、盐酸替扎尼定、盐酸氯丙嗪和巴氯芬对Ⅱ类屈肌反射的抑制作用。
