Linked Life Data

8628581

Source:http://linkedlifedata.com/resource/pubmed/id/8628581

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1996-6-25
pubmed:abstractText
The importance of N-methyl-D-aspartate (NMDA) receptor-mediated sensitization of central nervous system (CNS) neurons is well established in animal models of acute and chronic pain. A human model of central sensitization would be useful in screening new NMDA antagonists and establishing dose regimens for clinical trials in patients with pain related to sensitization of CNS neurons. We used this model to examine the effects of intravenous infusions of two centrally acting analgesics, the NMDA receptor antagonist ketamine and the morphine-like opioid agonist alfentanil. Twelve normal subjects completed a 3-session, randomized, double-blind, crossover study. From 25 to 60 min after capsaicin injection, subjects were given intravenous infusions of ketamine (mean dose: 32 mg), alfentanil (mean dose: 3075 micrograms), or saline placebo. Both drugs significantly reduced ongoing pain and pinprick-evoked hyperalgesia during the infusion. The reduction in allodynia evoked by light stroking was statistically significant only for alfentanil. Mean reduction +/- SEM relative to placebo were for ongoing pain: ketamine, 36 +/- 9%; alfentanil, 51 +/- 5%; area of pinprick hyperalgesia: ketamine, 34 +/- 7%; alfentanil, 35 +/- 7%; and area of mechanical allodynia: ketamine, 52 +/- 20%; alfentanil, 70 +/- 12%. Because the drugs were given systemically and produced side effects in all subjects, we cannot specify the site or sites of action nor conclusively rule out a non-specific 'active placebo' response as the cause for reduction of symptoms. Arguing against an 'active placebo' response, however, was the lack of analgesic effect of intravenous midazolam (mean dose; 3.4 mg, titrated to produce side effects of similar magnitude to ketamine and alfentanil) given at 145 min after capsaicin in 9 subjects who had received saline from 25 to 60 min. The results of this study suggest that neural systems sensitive to NMDA receptor antagonists and opioids participate in capsaicin-evoked pain phenomena, and support the feasibility of pharmacological studies using the intradermal capsaicin model.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0304-3959
pubmed:author
pubmed:issnType
Print
pubmed:volume
63
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
163-72
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed-meshheading:8628581-Adult, pubmed-meshheading:8628581-Alfentanil, pubmed-meshheading:8628581-Analgesics, pubmed-meshheading:8628581-Anesthetics, Intravenous, pubmed-meshheading:8628581-Capsaicin, pubmed-meshheading:8628581-Cross-Over Studies, pubmed-meshheading:8628581-Double-Blind Method, pubmed-meshheading:8628581-Female, pubmed-meshheading:8628581-Humans, pubmed-meshheading:8628581-Hyperalgesia, pubmed-meshheading:8628581-Infusions, Intravenous, pubmed-meshheading:8628581-Injections, Intradermal, pubmed-meshheading:8628581-Ketamine, pubmed-meshheading:8628581-Male, pubmed-meshheading:8628581-Midazolam, pubmed-meshheading:8628581-Pain, pubmed-meshheading:8628581-Pain Threshold, pubmed-meshheading:8628581-Palliative Care, pubmed-meshheading:8628581-Placebos, pubmed-meshheading:8628581-Receptors, N-Methyl-D-Aspartate, pubmed-meshheading:8628581-Skin
pubmed:year
1995
pubmed:articleTitle
Effects of intravenous ketamine, alfentanil, or placebo on pain, pinprick hyperalgesia, and allodynia produced by intradermal capsaicin in human subjects.
pubmed:affiliation
Neurobiology and Anesthesiology Branch, National Institute of Dental Research, Bethesda, MD 20892, USA.
pubmed:publicationType
Journal Article, Clinical Trial, Randomized Controlled Trial