Mokha S S, Goldsmith G E, Hellon R F, Puri R
Exp Brain Res. 1987;65(2):427-36. doi: 10.1007/BF00236316.
The effect of electrical stimulation of the preoptic area of the hypothalamus on the discharge of neurones in the marginal layer (lamina I) of the trigeminal nucleus caudalis was studied in the anaesthetised rat. There was a powerful suppression of the discharge evoked by noxious thermal stimuli in 49/49 specific nociceptor driven (nocireceptive) neurones. The inhibitory effect increased with graded increases in the intensity of preoptic stimulation. Stimulation, however, produced only a small reduction in the discharge of 14/17 cold receptive neurones. Thresholds for producing suppression of cold receptive neurones were generally higher than those for nocireceptive neurones. There was no effect on the activity of 12/12 low threshold mechanoreceptive neurones. The inhibitory action generated on the activity of nocireceptive neurones was reduced by electrolytic lesions in the nucleus raphe magnus (NRM) or the nucleus paragigantocellularis lateralis (PGCL) or the dorsolateral and ventrolateral periaqueductal gray matter (PAG). Lesions made in the ventral or dorsal aspect of PAG were, however, ineffective in reducing the suppression. It is suggested that the powerful descending inhibitory control of nociceptive transmission in the trigeminal nucleus caudalis is one of the neuronal mechanisms mediating analgesia from the preoptic area of the hypothalamus.
在麻醉大鼠中，研究了下丘脑视前区电刺激对三叉神经尾侧核边缘层（I层）神经元放电的影响。在49/49个由伤害性热刺激驱动的特定伤害感受器（伤害感受性）神经元中，伤害性热刺激诱发的放电受到强烈抑制。随着视前区刺激强度的逐渐增加，抑制作用增强。然而，刺激仅使14/17个冷感受神经元的放电略有减少。抑制冷感受神经元放电的阈值通常高于伤害感受性神经元。对12/12个低阈值机械感受神经元的活动没有影响。中缝大核（NRM）、外侧旁巨细胞核（PGCL）或导水管周围灰质背外侧和腹外侧（PAG）的电解损伤可减弱对伤害感受性神经元活动产生的抑制作用。然而，在PAG腹侧或背侧进行的损伤在减轻抑制方面无效。提示三叉神经尾侧核对伤害性传入的强大下行抑制控制是介导下丘脑视前区镇痛的神经元机制之一。
