Abstract
THAT opiate receptors may mediate the action of inhalation anaesthetics is evident from the fact that intravenous injection of naloxone decreases the pain threshold in rats during inhalation anaesthesia1,2. But inhalation anaesthetics have not only analgesic and hypnotic properties, they also cause undesirable depression of the cardiovascular system. To investigate whether opiate receptors mediate the cardiovascular response to inhalation anaesthesia we perfused continuously the cerebro-ventricular system of both conscious and anaesthetised dogs with naloxone. Effects of anaesthesia with and without naloxone perfusion were compared for blood pressure, heart rate and baroreflex activity. The constant perfusion technique was adopted to avoid the drastic transients of naloxone brain concentrations which occur following intravenous naloxone application3,4 and which might have masked the naloxone effects in recent reports5–7. We show here that (−)naloxone in contrast to (+)naloxone is capable of antagonising the circulatory effects of halothane anaesthesia from the fourth cerebral ventricle.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
