In rhesus monkeys, acute administration of levonantradol and nantradol produced signs of CNS depression, including ataxia with body sag, pupil dilation, ptosis, dozing, and reduced responsivity to external stimuli. Neither compound suppressed the morphine withdrawal syndrome; however, both alleviated the chronic abdominal contraction associated with withdrawal. The directly observable effects o...

Extracellular signal-regulated kinase (ERK), a mitogen-activated protein kinase (MAPK), transduces a broad range of extracellular stimuli into diverse intracellular responses. It has been reported that ERK is involved in the modulation of nociceptive information and central sensitization produced by intense noxious stimuli or peripheral tissue inflammation. Our previous studies showed that the ...

Morphine is a potent opioid analgesic. However, the repeated use of morphine causes tolerance and hyperalgesia. Neuroinflammation has been reported to be involved in morphine tolerance and withdrawal-induced hyperalgesia. The complement system is a crucial effector mechanism of immune responses. The present study investigated the roles of complement factor C5a and C5a receptor (C5aR) in the dev...

The relative involvement of kappa opioid receptors in the mediation of behavioral and neurochemical responses to withdrawal from chronic drug treatment with the opioid analgesic butorphanol was studied using in vivo microdialysis to detail extracellular fluid concentrations of glutamate and aspartate within the locus ceruleus. Sprague-Dawley rats were rendered opioid dependent after 3 days of i...

We investigated the ability of dextromethorphan, a clinically available NMDA receptor antagonist, to attenuate the behaviors and the expression of c-fos mRNA associated with acute morphine withdrawal in the 7-day-old rat. The intensity of the acute morphine withdrawal behaviors and the elevation in c-fos mRNA expression in the brain induced by acute morphine withdrawal were reduced by dextromet...

Zhou, Q. 2001, The Impact of Substance P (SP) N-Terminal Metabolite SP1-7 in Opioid Tolerance and Withdrawal. Acta Univ. Ups. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Pharmacy 260. 60 pp. Uppsala. ISBN 91-554-5174-8. The heptapeptide SP1-7, a metabolite of the neuroactive peptide substance P (SP), is suggested to play a role in opioid addiction and memory function. T...

OBJECTIVE To observe the effect of L-type calcium channel blocker like nimodipine on morphine's withdrawal when it was administered continuously along with morphine versus a single bolus dose of nimodipine, which was administered at the end of the experiment before the precipitation of withdrawal reaction in morphine-dependent rats. MATERIALS AND METHODS Four groups of adult male Wistar rats ...

We have shown previously that withdrawal from morphine induces immunosuppression in mice. The present study reports the effects of morphine withdrawal on infection with Salmonella enterica serovar Typhimurium. Mice were made dependent on morphine by the implantation of a slow-release morphine pellet for 96 h. Controls received a placebo pellet. Withdrawal was induced by pellet removal. Mice wer...