大鼠脑室注射四肽Asn-Ala-Gly-Ala引起的镇痛作用(英文)

Antinociceptive effect of intracerebroventricular injection of a tetrapeptide Asn-Ala-Gly-Ala in rats

icv四肽Asn-Ala-Gly-Ala(NAGA)能引起大鼠痛阈持续升高,并呈剂量依赖关系(0.03—0.24μmol/rat)。这一作用可被纳洛酮(icv.0.26mg·kg^(-1))翻转。icv甲硫氨酸脑啡肽抗血清或亮氨酸脑啡肽抗血清,能抑制NAGA引起的镇痛作用;icv强啡肽A_(1-13)抗血清或β-内啡肽抗血清不影响NAGA引起的镇痛作用。结果提示NAGA的镇痛作用可能与大鼠脑内甲硫氨酸脑啡肽和亮氨酸脑啡肽的释放有关。

The antinociceptive effect of in-tracerebroventricular injection (icv) of Asn-Ala-Gly-Ala (NAGA), a partial sequence of β-lipotropin, was studied in rats. The potassium iontophoresis-induced tail flick was used to measure the pain threshold. The antinociceptive effect of NAGA, which was dose-dependent (icv, 0.03 - 0-24 μmol/rat) and long-lasting (90 min) , was reversed by naloxone (icv, 0.26 mg·kg-1) and inhibited by anti-MEK serum (titre: 1:5000, 5 μl) or anti-LEK serum (titre: 1:5000, 5 μl). NAGA-induced antinociception was scarcely affected by anti-β-EP serum (titre: 1:30000, 5 μl ) or anti - Dyn A1-13 -serum ( litre : 1:30000, 5 μl). It was suggested that the antinociceptive effect of NAGA may be associ- ated with the release of met-enkephalin and leu-enkephalin in rat brain.