P2X2和P2X4受体在新生和成年大鼠延髓的表达

目的研究嘌呤能受体（purinergic receptors，P2）家族中P2X不同亚型在新生和成年SD大鼠延髓的表达。方法成年SD大鼠（6-8w）和新生SD大鼠（1-5d），各6只，雌雄不计，取延髓。应用免疫组织化学的方法和图像分析技术，比较P2X2和P2X4受体在新生和成年SD大鼠延髓的表达。结果P2X2和P2X4嘌呤受体的阳性神经元和阳性纤维在新生鼠和成年鼠的延髓都有广泛表达，主要分布在孤束核、Ⅻ颅神经核和延髓腹外侧区，延髓其他区域为散在的分布。成年鼠和新生鼠的P2X2受体均比P2X4受体表达水平高。在新生鼠延髓，P2X2和P2X4的表达水平均比成年鼠低。结论P2X2和P2X4阳性神经元和阳性纤维广泛分布在大鼠延髓，为ATP对心血管活动、呼吸活动和痛觉等的调节作用提供了结合位点，也有利于实验中P2X受体亚型阻断剂的选择。随着动物发育成熟，P2X2和P2X4表达水平均增加。

Expression of P2X2 and P2X4 receptors immunoreactivity in the medulla of neonatal and adult rats

Purpose Present study investigated the expression of P2X_2 and P2X_4 receptors in the medulla of neonatal and adult Sprague-Dawley(SD) rats. Methods Expression of P2X_2 and P2X_4 receptors was observed in the medulla of neonatal(1-5 d,n=6) and adult(6-8 wk,n=6) rats by using immunohistochemistry.The relative optical density(RA) of P2X_2 and P2X_4 receptors immunoreactivity was calculated by software of ImageMeasure. Results There was an extensive staining with both P2X_2 and P2X_4 receptors positive neurons and nerve fibers localized in medulla oblongata.It was mainly localization in the nucleus tractus solitarius(NTS),XII nucleus(XII) and ventrolateral medulla(VLM) of medulla oblongata.It also scattered throughout rest of medulla.Expression of P2X_2 receptors immunoreactivity was higher than that of P2X_4 in both neonatal and adult SD rats.The RODs of P2X_2 and P2X_4 receptors immunoreactivity were both lower in neonatal rats than that in adult rats. Conclusions Data indicate a widespread distribution for positive neurons and nerve fibers of P2X_2 and P2X_4 receptors in medulla oblongata of rats.These P2X_2 and P2X_4 receptors immunoreactivity provide the functional sites for ATP to regulate cardiovascular activity,respiration,pain and so on.It is of great benefit to choose antagonist of P2X subtypes.Expression of P2X_2 and P2X_4 receptors in medulla oblongata of rats increased both with maturation.