Naloxazone pretreatment modifies cardiorespiratory, temperature, and behavioral effects of morphine.

Abstract

Behavioral and cardiorespiratory responses to a lethal dose of morphine were evaluated in rats pretreated with saline or naloxazone, an antagonist of high-affinity mu 1 opioid receptors. Pretreatment with naloxazone significantly blocked morphine analgesia, catalepsy and hypothermia at a dose which completely eliminated high-affinity binding in brain membranes. Moreover, naloxazone significantly attenuated the morphine-induced hypotension and respiratory depression, whereas morphine-induced bradycardia was less affected. Results indicate that subpopulations of mu receptors may mediate selective behavioral and cardiorespiratory responses to morphine.

• Authors: J W Holaday, G W Pasternak, A I Faden
• Journal: Neuroscience letters (Neurosci Lett) Vol. 37 Issue 2 Pg. 199-204 (Jun 16 1983) ISSN: 0304-3940 [Print] Ireland
• PMID: 6308526 (Publication Type: Journal Article)

Chemical References

• Receptors, Opioid
• Naloxone
• naloxazone
• Morphine

Topics

• Animals
• Blood Pressure (drug effects)
• Body Temperature Regulation (drug effects)
• Dose-Response Relationship, Drug
• Heart Rate (drug effects)
• Male
• Morphine (pharmacology)
• Motor Activity (drug effects)
• Naloxone (analogs & derivatives, pharmacology)
• Nociceptors (drug effects)
• Premedication
• Rats
• Rats, Inbred Strains
• Receptors, Opioid (drug effects)
• Respiration (drug effects)