title: Ethanol-induced depression of hypoxic drive and reversal by naloxone--a sex difference.
abstract: The effects of ethanol ingestion and subsequent intravenously administered naloxone on the ventilatory response to hypercapnic hypoxia in 8 normal males and 8 normal females were examined. The responses of controls were lower in the females (-0.63 +/- 0.07 L/min/% SaO2) than the males (-1.11 +/- 0.18 L/min/% SaO2). Alcohol depressed the male response to a mean of -0.50 +/- 0.08 L/min/%SaO2 (p less than 0.01) but increased the mean female response to -0.87 +/- 0.11 L/min/%SaO2 (p less than 0.01). Naloxone reversed the ethanol-induced depression of the hypercapnic hypoxic response in males, but had no effect on the female response. In males there was a direct correlation between the magnitude of the initial hypoxic response and the extent of depression by ethanol; the higher the response the greater the depression. Females showed a significant direct correlation between the blood alcohol and the increase in hypercapnic hypoxic slope, whereas males showed a weaker inverse correlation to blood alcohol level. These results demonstrate that ethanol depresses male but not female hypoxic ventilatory responsiveness and suggest that this is mediated by opioid-like mechanisms. Because the alcohol-induced depression was seen in subjects with a high control hypoxic response, the male-female difference might simply reflect initially lower control responses in females. This suggests a qualitative difference in hypoxic ventilatory control mechanisms between sexes.
authors.affiliation: Department of Medicine, University of Sydney, N.S.W. Australia.
authors.forename: V B
authors.initials: VB
authors.lastname: McCauley
authors.forename: R R
authors.initials: RR
authors.lastname: Grunstein
authors.forename: C E
authors.initials: CE
authors.lastname: Sullivan
mesh_terms: D000328:Adult; D000431:Ethanol / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D012119:Respiration / Q000187:drug effects*; D012727:Sex Characteristics
chemical_list: D009270:Naloxone; D000431:Ethanol