Lu S G, Mei J
Department of Brain and Nerve, Xian Medical University.
Sheng Li Xue Bao. 1992 Aug;44(4):362-9.
The inhibitory effects of dopamine (DA) applied spinally on the wide dynamic range (WDR) neurons of dorsal horn in rats were studied with extracellular recording technique. 54 WDR units were tested from 43 rats. With a dosage of DA from 0.26 x 10(-6) to 1.58 x 10(-6) mol/kg, the inhibitory effect of the neurotransmitter on the responses of dorsal horn neurons to noxious transcutaneous electrical stimulation exhibited a gradual increase. After DA (0.52 x 10(-6) mol/kg) administration, the inhibitory effect of DA began to appear in 5 min and reach to maximum in 15 min, whereupon the maximum level could be maintained for about 25 min. This effect of DA could be reversed completely by dopaminergic receptor antagonist, droperidol (0.66 x 10(-6) mol/kg) but not by 2.65 x 10(-6) mol/kg phentolamine or 1.37 x 10(-6) mol/kg naloxone. The results of the present investigation suggest that DA may be involved in the modulation of nociception at the spinal level as an independent neurotransmitter.
采用细胞外记录技术，研究了脊髓应用多巴胺（DA）对大鼠背角广动力范围（WDR）神经元的抑制作用。从43只大鼠中检测了54个WDR单位。当DA剂量为0.26×10⁻⁶至1.58×10⁻⁶mol/kg时，该神经递质对背角神经元对有害经皮电刺激反应的抑制作用呈逐渐增强趋势。给予DA（0.52×10⁻⁶mol/kg）后，DA的抑制作用在5分钟开始出现，15分钟达到最大，随后最大水平可维持约25分钟。DA的这种作用可被多巴胺能受体拮抗剂氟哌利多（0.66×10⁻⁶mol/kg）完全逆转，但不能被2.65×10⁻⁶mol/kg酚妥拉明或1.37×10⁻⁶mol/kg纳洛酮逆转。本研究结果提示，DA可能作为一种独立的神经递质参与脊髓水平的伤害性感受调制。
