Mu-Opioid Receptor mRNA Regulation During Morphine Tolerance in the Rat Peripheral Nervous System

Abstract

The peripheral nervous system is a possible site of opioid receptor tolerance. We show the development of behavioral tolerance and mu-opioid receptor mRNA down-regulation in the dorsal root ganglia in rats after chronic morphine treatment. Both this mRNA down-regulation and behavioral tolerance reverse after 24 h of naloxone treatment.