BACKGROUND Noroxymorphone is one of the major metabolites of oxycodone. Although oxycodone is commonly used in the treatment of acute and chronic pain, little is known about the antinociceptive effects of noroxymorphone. We present an in vivo pharmacological characterization of noroxymorphone in rats. METHODS The antinociceptive properties of noroxymorphone were studied with thermal and mecha...

BACKGROUND Postoperative pruritus, nausea, and vomiting are common side effects of intrathecal or epidural opioids. Intravenous ondansetron has been used for postoperative emesis. However, there are no reports regarding epidural ondansetron. Two studies were conducted to evaluate the prophylactic effects of epidural ondansetron for opioid-induced pruritus, nausea, and vomiting. METHODS Neurot...

We compared effects on motor function of four peptides belonging to the dynorphin family--dynorphin-(1-17) (DYN-(1-17], dynorphin-(1-13) (DYN-(1-13], dynorphin-(1-8) (DYN-(1-8] and alpha-neo-endorphin (alpha NE). After intrathecal administration, each of these peptides produced dose-related, flaccid, hindlimb paralysis, with the order of potency being DYN-(1-17) greater than DYN-(1-13) greater ...

Low molecular weight opioid peptide esters (OPE) could become a class of analgesics with different side effect profiles than current opiates. OPE may have sufficient plasma stability to cross the blood brain barrier (BBB), undergo ester hydrolysis and produce analgesia. OPE of dipeptides, tyr-pro and tyr-gly conjugated to ethanol have a structure similar to the anesthestic agent, etomidate. Bas...

Pruritus is a troublesome side-effect of neuraxial (epidural and intrathecal) opioids. Sometimes it may be more unpleasant than pain itself. The prevention and treatment still remains a challenge. A variety of medications with different mechanisms of action have been used for the prevention and treatment of opioid-induced pruritus, with mixed results. The aim of this article is to review the cu...

We evaluated the effect of buprenorphine, a mixed agonist for μ-opioid receptors and nociceptin/orphanin FQ peptide (NOP) receptors, in neuropathic rats, using the paw pressure test. Buprenorphine, administered i.p. at 50, but not 20, μg/kg, exhibited naloxone-reversible analgesic activity in naïve rats. In contrast, buprenorphine at 0.5 - 20 μg/kg produced a naloxonesensitive antihyperalgesic ...

Spinally transected rats given legshock whenever one hindleg is extended learn to maintain a flexion response that decreases net shock exposure. Prior exposure to response-independent (noncontingent) shock prevents learning. This behavioral deficit was eliminated by systemic administration of the nonselective opioid antagonist naltrexone (Experiment 1). The deficit was also blocked by intrathec...

The present study was conducted to determine whether cutaneous itch involves mu-opioid receptors in either of the spinal cord or lower brainstem or in both regions in mice. An intraplantar injection of serotonin hydrochloride (100 nmol/site) induced biting, an itch-related behavior. The behavior was inhibited by subcutaneous (0.3-1 mg/kg) and intracisternal (1--10 nmol/site), but not intratheca...