Linked Life Data

9862403

Source:http://linkedlifedata.com/resource/pubmed/id/9862403

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1999-2-25
pubmed:abstractText
The purpose of the present investigation was to examine the development of tolerance to the rate-suppressing effects of mu and kappa opioids in rats administered either 3.0 (low) or 30 (high) mg/kg per day of butorphanol, an opioid with low relative efficacy at the mu receptor. The mu opioids butorphanol, buprenorphine, morphine, fentanyl and sufentanil, and the kappa opioid U50,488 dose-dependently suppressed responding under all conditions examined. In rats administered the low maintenance dose of butorphanol, tolerance developed to the effects of butorphanol, buprenorphine and morphine, but not to fentanyl and sufentanil. In rats administered the high maintenance dose, tolerance developed to all of the mu opioids examined. In both treatment groups, the degree to which tolerance developed was greater for butorphanol and buprenorphine than for morphine, fentanyl and sufentanil; and the degree to which tolerance developed to these mu opioids was greater in rats administered the high maintenance dose of butorphanol. The tolerance that developed to morphine, fentanyl and sufentanil was not altered when tested at both 23 and 47 h following the previous maintenance dose of butorphanol, suggesting that these changes were not due to any acute pharmacological interactions between butorphanol and the test compound (i.e., antagonism). Tolerance was also conferred to the kappa opioid U50,488 in both groups of rats, and in rats administered the high maintenance dose, this effect was obtained when tested 23 and 47 h following the previous maintenance dose of butorphanol. Physical dependence developed in rats administered the high maintenance dose of butorphanol, as evidenced by the development of enhanced sensitivity to the rate-suppressing effects of naloxone, and the finding that 30 mg/kg naloxone decreased body weight in a time-dependent manner. No physical dependence was apparent in rats administered the low maintenance dose of butorphanol. These data suggest that during chronic treatment with butorphanol, (1) greater degrees of tolerance are conferred to drugs possessing low efficacy at the mu opioid receptor, (2) tolerance is enhanced as the maintenance dose of the toleragen is increased, and (3) mu-opioid tolerance may be observed under conditions that do not produce mu-opioid dependence.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0033-3158
pubmed:author
pubmed:issnType
Print
pubmed:volume
140
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
57-68
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Tolerance and cross-tolerance to the rate-suppressing effects of opioids in butorphanol-treated rats: influence of maintenance dose and relative efficacy at the mu receptor.
pubmed:affiliation
Department of Psychology, University of North Carolina at Chapel Hill, 27599-3270, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.