Tolerance, Opioid-induced Allodynia and Withdrawal Associated Allodynia in Infant and Young Rats.
From: Department of Anesthesia, Stanford University School of Medicine, Stanford, CA 94305, USA.
Neuroscience
- Publish Date: Jan 2007
- ISSN: 0306-4522
- Volume: 144
- Issue: 1
- Pages: 247-62
- Medium: Print
- Language: English
- Citation (JAMA): Zissen M H, Zhang G, McKelvy A, et al. Tolerance, Opioid-induced Allodynia and Withdrawal Associated Allodynia in Infant and Young Rats.. Neuroscience Jan 2007;144:247-62
Abstract
Our laboratory has previously characterized age-dependent changes in nociception upon acute morphine withdrawal. This study characterizes changes in mechanical and thermal nociception following acute, intermittent, or continuous morphine administration in infant (postnatal days 5-8) and young (postnatal days 19-21) rats. Morphine was given as a single acute administration (AM), intermittently twice a day for 3 days (IM), or continuously for 72 h via pump (CM). AM did not produce long-term changes in mechanical or thermal nociception in either infant or young rats. CM produced changes in mechanical nociception that included the development of tolerance, opioid-induced mechanical allodynia and withdrawal-associated mechanical allodynia in young rats, but only tolerance and a prolonged withdrawal-associated mechanical allodynia in infant rats. IM produced withdrawal-associated mechanical allodynia in both infant and young rats. Measuring paw withdrawal responses to thermal stimuli, infant and young rats showed tolerance without opioid-induced thermal hyperalgesia or withdrawal-associated thermal hyperalgesia following CM. In contrast to CM, withdrawal-associated thermal hyperalgesia was seen in both ages following IM. In conclusion, CM versus IM differentially modified mechanical and thermal nociception, suggesting that opioid-dependent thermal hyperalgesia and mechanical allodynia can be dissociated from each other in infant and young rats. Furthermore, tolerance, opioid-induced hypersensitivity, and withdrawal-associated hypersensitivity are age-specific and may be mediated by distinct mechanisms.
Mesh Headings (Keywords): Aging, Analgesics, Opioid, Animals, Animals, Newborn, Behavior, Animal, Drug Implants, Drug Tolerance, Female, Heat, Hyperalgesia, Infusion Pumps, Implantable, Injections, Subcutaneous, Male, Morphine, Pain, Pain Measurement, Pain Threshold, Physical Stimulation, Rats, Rats, Sprague-Dawley, Reaction Time, Substance Withdrawal Syndrome, Weight Gain
Check for Full Text / PubMed Unique Identifier (PMID): 17055659
This abstract is part of PubMed, a service of the U.S. National Library of Medicine. PubMed includes more than 17 million citations from MEDLINE and other life science journals for biomedical articles. See Copyright and Disclaimers.
Linked medical terms appearing on this page are added by Healia to help readers find more information and are not part of the original PubMed document.
The data herein was last updated on July 8th, 2008 and may not reflect the most current and accurate data available from NLM.