异氟醚、安氟醚麻醉诱导期大鼠边缘系统部分核团一氧化氮合酶阳性神经元的改变

Changes in nitric oxide synthase (NOS) positive neurons in limbic system induced by isoflurane or enflurane in rats

目的 观察异氟醚、安氟醚诱导麻醉对大鼠边缘系统部分核团一氧化氮合酶(NOS)阳性神经元的的改变,探讨异氟醚、安氟醚麻醉诱导期的作用机制。方法 18只SD雄性大鼠随机分为3组:对照组、安氟醚组、异氟醚组。对照组动物除不吸入麻醉气体外,其他条件均与两麻醉组相同。安氟醚组、异氟醚组大鼠分别吸入2％安氟醚或2％异氟醚至步态不稳、一侧肢体着地,即翻正反射即将消失时,移出麻醉箱,立即取标本。用NADPH-d组化法观察吸入2％异氟醚、2％安氟醚诱导麻醉对大鼠边缘系统部分核团NOS阳性神经元数量和灰度值的影响。结果 安氟醚组大鼠脑的外侧隔核、下丘脑室旁核、下丘脑室周核、视上核、杏仁基外侧核和伏隔核等6个核团NOS阳性神经元数量和染色深度均低于对照组,异氟醚组在上述6个核团中NOS阳性神经元的数量和平均灰度水平也低于对照组,下丘脑室周核和视上核NOS阳性神经元数目有减少趋势,但与对照组比较差异无统计学意义(P>0.05),其余核团与对照组比较差别均有显著性(P<0.01)。结论 异氟醚、安氟醚诱导期的作用机理可能与边缘系统部分核团NOS阳性神经元的改变有关。

Objective To investigate the changes in NOS positive neurons in some nuclei in limbic system induced by isoflurane or enflurane anesthesia and the underlying mechanism. Methods Eighteen male SD rats aged 3-4 months weighing 200-250 g were randomly divided into 3 groups with 6 animals in each group : control group; isoflurane group and enflurane group. In isoflurane and enflurane groups the animals received 2 % isoflurane or enflurane in a special glass box until the animals started staggering before loss of righting reflex. Then the animals were immediately decapitated. Brains were removed and sliced . The NOS positive neurons in the 6 nuclei (lateral septal nucleus, basolateral amygdaloid nucleus, hypothalamic paraventricular nucleus, hypothalamic periventricular nucleus, supraoptic nucleus and accumbens nucleus) in limbic system were detected using NADPH-d histochemical staining. Results The induction time was 2.1±0.4min in isoflurane group and 2.6±0.5 min in euflurane group. The intensity of staining and the number of NOS positive neurons in the 6 nuclei were significantly decreased in both enflurane and isoflurane groups compared to the control group, but the decrease in the number of NOS positive neurons in hypothalamic periventricular and supraoptic nuclei in isoflurane group was not statistically significant (P > 0.05) compared to control group. Conclusion Induction of anesthesia with isoflurane or enflurane decreases the number of NOS positive neurons in the 6 nuclei in limbic system. The changes in NOS positive neurons in limbic system may be involved in the mechanism of isoflurane and enflurane anesthesia.