髓鞘内不同浓度甘丙肽拮抗剂对屈肌运动的相反效应

目的 :了解脊髓中不同剂量甘丙肽拮抗剂M35和M40对甘丙肽抑制屈肌运动作用的影响。方法 :电刺激小腿腹神经引起小腿屈肌收缩时 ,观察髓鞘内联合注入甘丙肽和不同浓度拮抗剂时屈肌张力的改变。结果注入0 0 1、 0 0 3及 0 1μmol/LM35时 ,0 1μmol/L甘丙肽对屈肌张力抑制率从 - 2 9 2 %改变至± 15 1%、 - 2 5 %及 -17 8% ;但 1及 3μmol/L的M35使甘丙肽抑制率分别增强至 - 5 1 9%及 - 6 5 6 %。而给于 0 0 1及 0 0 3μmol/LM40时 ,甘丙肽抑制率增至 - 5 6 7%及 - 41 6 % ,0 3、 1及 3μmol/LM40使甘丙肽抑制率分别改变为 - 6 8%、 +12 2 %及 +30 4%。结论　低浓度M35为甘丙肽拮抗剂 ,高浓度M35有甘丙肽激动剂作用 ;低浓度M40为甘丙肽激动剂 ,高浓度M40有甘丙太拮抗剂效应。脊髓神经元可能存在不同甘丙肽亚型受体。

The Adverse Effect of Intrathecal Galanin Antagonists at Different Doses on Flexor Contractions in the Rat

Objective:The effects of intrathecal galanin(Gal) antagonist M35 or M40 at different concentrations on the Gal-evoked inhibition of flexor contractions were measured.Methods:Observe the change of flexor contractile tension induved by electrial stimulation of the sural nerve when coadministration 0 1 μ mol/L galanin with its antagonists M35 or M40 at different concentrations. Results:Coadministration of 0 01,0 03 and 0 1 μ mol/L M35 diminished the Gal-evoked inhibition of flexor contractile tension from -29 2% to +15 1%?-2 5% and -17 8%;while 1 and 3 μ mol/L enlarged it to -51 9% and -65 6% Coadministration of 0 01 and 0 03 μ mol/L M40 increased it to -56 7% and -41 6%;while 0 3,1 and 3 μ mol/L M40 diminished it to -6 8%?+12 2% and +30 4% Conchusion: M35 at low concentrations antagonizes the effect of Gal and at high concentrations acts as a Gal receptor agonist. Whereas M40 in high doses antagonizes the effect of Gal and in low doses exerts an agonist action. There may be different Gal subtype receptors in the neurons of spinal cords.