ATP对大鼠体温调节的影响

通过腹腔注射及在体和离体下丘脑视前区(POAH)微量给药的方法，观测ATP对大鼠体温调节的影响。结果显示：(1)腹腔注射ATP有明显降体温作用，降温幅度和作用时间具量-效关系。去甲肾上腺素β受体阻断剂(心得静)可抑制ATP的降温作用，表明ATP在外周的降温作用可能是由交感神经系统中介的；(2)POAH微量注入低剂量的ATP使体温下降，其作用被ATP受体P₂的阻断剂(ReactiveBlue2)所阻断，表明ATP的降温作用是通过P₂型受体起作用的；注入高剂量的ATP使体温上升，其机制与ATP络合Ca²⁺的作用相关；(3)离体脑片给在体的研究以佐证，高和低浓度的ATP分别抑制和易化POAH热敏神经元的自发放电活动，表明ATP可能是直接通过影响POAH温敏神经元放电活动参与体温调节的。

Effects of ATP on the Thermoregulation in the Rat

Adenosine triphosphate (ATP) is a kind of purinergic neurotransmitter. By means of intraperitoneal injection, intrapreoptical microinjection and Neuronal study of preoptic area of hypothalamic (POAH) tissue slice, effects of ATP on thermoregulation in the rat were investigated. The results are as follows. (1) there occurred an appreciable hypothermia followed by intraperitoneal injection of ATP with dose-dependent effect. Pindolol, a noradrenaline-β receptor antagonist, abolished the effect and suggested that the Tb fall was presumptively mediated by sympathetic nervous system; (2) Intrapreoptical administration of ATP with lower concentration decreased the body temperature, but the effect could be dramatically eliminated by reactive blue 2, a nonselective P₂-purinoceptor antagonist, hinting the likelihood that purinoceptors play an important role in thermoregulation; The higher doses, however, elicited the body temperature rise, which might be attributed to the chelating effect of ATP on free extracellular calcium; (3) The effects of ATP on the warm-sensitive neurons in POAH slices gave further evidence for the result showed in vivo, the higher and lower concentrations of ATP inhibited and facilitated the spontaneous firing of warm-sensitive neurons respectively, which suggested that ATP involved in thermoregulation by direct affecting the warm-sensitive neuron activity in POAH.