Herman J K, O'Halloran K D, Mitchell G S, Bisgard G E
Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, 53706, USA.
Respir Physiol. 1999 Oct 15;118(1):25-37. doi: 10.1016/s0034-5687(99)00070-5.
Ventilatory acclimatization to hypoxia (VAH) is the time-dependent increase in ventilation that occurs during sustained hypoxia. As serotonin (5-HT) has been reported to be an important modulator of respiratory output, 5-HT may also play a role in VAH. Methysergide (a broad-spectrum 5-HT antagonist), was given to awake goats (1 mg kg(-1) i.v.) 30 min prior to being exposed to 4 h of isocapnic hypoxia. Although methysergide slightly decreased arterial pH, presumably due to a non-significant increase in arterial P(CO2), it did not alter normoxic ventilation. Following methysergide, the expired minute ventilation (VE) was significantly elevated above the control (saline) response after 30 min of hypoxia, but methysergide did not otherwise alter VAH. We repeated the study in the same goats using ketanserin, a specific 5-HT2A/2C receptor antagonist (1.2 mg kg(-1) i.v.). Ketanserin had no effect on the acute hypoxic ventilatory response, or on VAH. We conclude that while 5-HT modulates the acute hypoxic ventilatory response in goats, it does not appear to act through the 5-HT2A/2C receptor subtypes.
通气对低氧的习服（VAH）是指在持续性低氧期间通气随时间的增加。由于血清素（5-羟色胺，5-HT）据报道是呼吸输出的重要调节因子，5-HT可能在VAH中也发挥作用。在清醒山羊暴露于4小时等碳酸血症性低氧前30分钟，静脉注射麦角新碱（一种广谱5-HT拮抗剂，1毫克/千克）。尽管麦角新碱使动脉pH略有降低，推测是由于动脉血二氧化碳分压（P(CO2)）非显著性升高所致，但它并未改变常氧通气。注射麦角新碱后，低氧30分钟时的每分钟呼气通气量（VE）显著高于对照（生理盐水）反应，但麦角新碱在其他方面并未改变VAH。我们使用特异性5-HT2A/2C受体拮抗剂酮色林（1.2毫克/千克，静脉注射）在同一批山羊中重复了该研究。酮色林对急性低氧通气反应或VAH均无影响。我们得出结论，虽然5-HT调节山羊的急性低氧通气反应，但它似乎并非通过5-HT2A/2C受体亚型发挥作用。
