Komisaruk B R, Wallman J
Brain Res. 1977 Nov 25;137(1):85-107. doi: 10.1016/0006-8993(77)91014-9.
The present studies extend previous findings that probing the vaginal cervix of rats blocks withdrawal reflexes and induces immobilization44. In the present studies, we report that this effect is apparently not due to an action on the final motor pathway, for limb or facial movement induced by electrical stimulation of the pyramidal tract was not suppressed by the probing. In contrast, the sensory response of neurons in the ventrobasal complex of the thalamus to noxious pinch stimulation was markedly attenuated by probing the vaginal cervix. However, the response of these neurons to gentle tactile stimulation was not attenuated, indicating a selective antinociceptive effect of the probing. The antinociceptive effect was not necessarily related to changes in arousal. These findings were supported by behavioral studies in which probing the vaginal cervix blocked vocalization in response to tail shock, and elevated the current threshold for eliciting vocalization in response to tail shock. Furthermore, during the probing, the rats were found to be capable of vocalizing in response to presumably non-noxious (lifting) stimulation, even though their vocalization response to noxious tail shock was suppresed. These studies suggest that probing the vaginal cervix rats exerts an analgesic action.
目前的研究扩展了先前的发现，即探测大鼠阴道宫颈会阻断退缩反射并导致不动44。在目前的研究中，我们报告这种效应显然不是由于对最终运动通路的作用，因为电刺激锥体束所诱发的肢体或面部运动并未因探测而受到抑制。相反，通过探测阴道宫颈，丘脑腹侧基底核中的神经元对有害捏压刺激的感觉反应明显减弱。然而，这些神经元对轻柔触觉刺激的反应并未减弱，表明探测具有选择性的抗伤害感受作用。这种抗伤害感受作用不一定与觉醒的变化有关。行为学研究支持了这些发现，其中探测阴道宫颈可阻断对尾部电击的发声反应，并提高引发对尾部电击发声反应的电流阈值。此外，在探测过程中，发现大鼠能够对大概是非有害的（提起）刺激做出发声反应，尽管它们对有害尾部电击的发声反应受到了抑制。这些研究表明，探测大鼠阴道宫颈会产生镇痛作用。
