Morphine has latent deleterious effects on the ventilatory responses to a hypoxic-hypercapnic challenge

• 作者: Alex P. Young Fraser Henderson Jr. James N. Bates Joseph F. Discala Lisa A. Palmer Ryan B. Gruber Stephen J. Lewis Walter J. May
• 来源期刊: 分子和综合生理学期刊(英文)
• 学科: 医学
• 关键词: MORPHINE Hypoxia-Hypercapnia MINUTE Ventilation Arterial Blood Gases CONSCIOUS Rats
• 年，卷（期）: 2013,（3）
• 页码范围: 134-145
• 页数: 12页
• 分类号: R73

摘要

This study explored the concept that morphine has latent deleterious actions on the ventilatory control systems that respond to a hypoxic-hypercapnic challenge. In this study, we examined the ventilatory responses elicited by hypoxic-hypercapnic challenge in conscious rats at a time when the effects of morphine (10 mg/kg) on arterial blood-gas chemistry and minute ventilation had subsided. Morphine induced pronounced changes in arterial blood-gas chemistry (e.g., an increase in pCO2, decreases in pO2 and sO2) and decreases in minute ventilation. Despite the complete resolution of the morphine-induced changes in arterial blood-gas chemistry and minute ventilation and almost complete resolution of the effects on peak inspiratory flow and peak expiratory flow, subsequent exposure to hypoxic-hypercapnic challenge elicited markedly blunted increases in minute ventilation and in peak inspiratory and expiratory flows. These findings demonstrate that 1) the changes in arterial blood-gas chemistry elicited by morphine parallel changes in minute ventilation rather than PIF and PEF, and 2) morphine has latent untoward effects on the ventilatory responses to hypoxic-hypercapnic challenge. These novel findings raise the possibility that patients deemed to have recovered from the acute ventilatory depresssant effects of morphine may still be susceptible to the latent effects of this opioid analgesic. The mechanisms underlying these latent effects remain to be elucidated.