Neural mechanisms of thermo-regulation : Identification of the cutaneous vasomotor center

热调节的神经机制，特别是从所谓的下丘脑热调节中心到皮肤血管收缩纤维的途径，目前尚不清楚。兔子的耳朵是体温调节器官之一，控制着血液的流动。我们之前提出，被下丘脑背内侧电刺激激发的延髓吻侧腹侧网状脊髓神经元（Cu神经元）是耳皮肤血管收缩纤维的前运动神经元（Kishi, et al., 1999）。在本项目中，我们同时记录了耳部交感血管收缩纤维和延髓吻侧腹侧网状脊髓神经元的活动，并从它们的节律性活动的角度分析了它们的自发活动。耳铜神经元和皮血管收缩纤维无心周期相关节律活动，而肾交感神经有明显的心周期相关节律活动。铜神经元和皮肤血管收缩纤维均具有呼吸相关活性。铜神经元活动的呼吸相关波动的调节程度与皮肤血管收缩纤维的调节程度几乎相同。下丘脑背内侧侧对刺激的反应和Cu神经元的自发活动表明这些Cu神经元是皮肤血管收缩纤维的前运动神经元。

Neural mechanisms of thermo-regulation, especially the pathway from so called thermo-regulatory center of the hypothalamus to the cutaneous vasoconstrictor fibers has been poorly understood. The ear of the rabbit is one of the thermo-regulatory organ, controlling its blood flow. We previously proposed that the reticulo-spinal neurons (Cu neurons) in the rostral ventral medulla that excited by the electrical stimulation of the dorso-medial hypothalamus were premotor neurons for cutaneous vasoconstrictor fibers of the ear (Kishi, et al., 1999). In the present project, we simultaneously recorded activities of the ear sympathetic vasoconstrictor fibers and the reticulo-spinal neurons in the rostral ventral medulla and analyzed their spontaneous activity in the point of view of their rhythmic activities.Cu neurons and cutaneous vasoconstrictor fibers of the ear had not cardiac cycle-related rhythmic activity, but renal sympathetic nerve shown clear cardiac cycle-related rhythmic activity. Both Cu neurons and cutaneous vasoconstrictor fibers had respiration-related activity. The degree of modulation of the respiratory-related fluctuation of the activity of the Cu neuron was almost same as that of cutaneous vasoconstrictor fibers.The responsiveness to the stimulation of the dorso-medial hypothalamus and the spontaneous activity of the Cu neurons indicated that these Cu neurons were premotor neurons for the cutaneous vasoconstrictor fibers.