中枢β—内啡肽和5—羟色胺在低氧通气调控中的关系

实验在去双侧外周化学感受器传入的麻醉雄性家兔上进行。给动物吸低氧混合气(10%O_2于N_2中)导致通气抑制后,从动物侧脑室注入β-内啡肽拮抗剂纳洛酮使抑制的通气被“翻转”;注入拟似剂羟甲芬太尼则使抑制更加深化。此时中枢5-羟色胺含量均较给药前明显升高。给动物注入外源性5-羟色胺后,中枢β-内啡肽含量较给药前明显下降,此时通气回复至对照水平。结果提示:中枢β-内啡肽系统是引起低氧通气抑制的基本和直接因素,而5-羟色胺系统则是作为一种神经调质,通过调制其β-内啡肽活动而间接对低氧通气反应产生影响。

Relationship between central beta-endorphins and serotonin systems in mechanism of hypoxic ventilatory regulation]

Experiments were performed on anesthetized bilaterally chemodenervated rabbits. After giving hypoxic gas mixture (10% O2 in N2) to animals to cause ventilatory inhibition, lateral ventricle applications of beta-endorphins (beta-EP) antagonist naloxone (Nlx) and agonist ohmefentanyl (OMF) respectively reduced and enhanced hypoxia-induced ventilatory inhibition. Meanwhile the level of central serotonin (5-HT) was obviously increased more than that before the drug administration. Injection of exogenous 5-HT into rabbit lateral ventricle induced central beta-EP content to decrease markedly while minute ventilation (VE) was returned to control at the same time. The results suggest that beta-EP system in CNS is the basic and direct element in the regulatory mechanism of hypoxic ventilatory inhibition, and central 5-HT system only acts as a neuromodulator in modulating the activity of beta-EP system to indirectly affect ventilatory response to hypoxia.