Spinal administration of selective opioid antagonists in amphibians: evidence for an opioid unireceptor.
Life Sci
; 64(10): PL125-30, 1999.
Article
in En
| MEDLINE
| ID: mdl-10096442
In mammals, opioids act by interactions with three distinct types of receptors: mu, delta, or kappa opioid receptors. Using a novel assay of antinociception in the Northern grass frog, Rana pipiens, previous work demonstrated that selective mu, delta, or kappa opioids produced a potent antinociception when administered by the spinal route. The relative potency of this effect was highly correlated to that found in mammals. Present studies employing selective opioid antagonists, beta-FNA, NTI, or nor-BNI demonstrated that, in general, these antagonists were not selective in the amphibian model. These data have implications for the functional evolution of opioid receptors in vertebrates and suggest that the tested mu, delta, and kappa opioids mediate antinociception via a single type of opioid receptor in amphibians, termed the unireceptor.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Rana pipiens
/
Receptors, Opioid
/
Narcotic Antagonists
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Life Sci
Year:
1999
Document type:
Article