Functional activity of the cannabinoid 1 receptor is not affected by opioid antagonists in the rat brain / 대한마취과학회지
Korean Journal of Anesthesiology
;
: 257-261, 2013.
Article
Dans Anglais
| WPRIM
| ID: wpr-49133
ABSTRACT
BACKGROUND:
WIN55212-2 is a synthetic cannabinoid agonist and selective to cannabinoid 1 (CB1) receptors, which are distributed mainly in the central nervous system. Opioid receptors and CB1 receptors have several similarities in terms of their intracellular signal transduction mechanisms, distributions, and pharmacological action. Several studies have therefore sought to describe the functional interactions between opioids and cannabinoids at the cellular and behavioral levels. The present study investigated agonist-stimulated [35S]GTPgammaS binding by WIN55212-2 in rat brain membranes and determined the antagonism by selective opioid antagonists at the level of receptor-ligand interaction and intracellular signal transduction.METHODS:
Sprague-Dawley rats (male, n = 20) were euthanized for the preparation of brain membranes. In agonist-stimulated [35S]GTPgammaS binding by WIN55212-2, the values of EC50 and maximum stimulation (% over basal) were determined in the absence or presence of the micro, kappa and delta opioid receptor antagonists naloxone (20 nM), norbinaltorphimine (3 nM), and naltrindole (3 nM), respectively. Ke values for opioid antagonist inhibition in the absence or presence of each opioid receptor antagonist were calculated using the following equation [nanomolar antagonist] / (dose ratio of EC50 - 1).RESULTS:
In WIN55212-2-stimulated [35S]GTPgammaS binding in the rat brain membranes, the values of EC50 and maximum stimulation (% over basal) were 154 +/- 39.5 nM and 27.6 +/- 5.3% over basal, respectively. Addition of selective opioid antagonists did not produce a significant rightward shift in the WIN55212-2 concentration-response curve, and Ke values were not applicable.CONCLUSIONS:
Our results suggest that the functional activity of WIN55212-2-stimulated [35S]GTPgammaS binding was not affected by opioid antagonists in the rat brain membranes. Although the exact mechanism remains unclear, our results may partially elucidate their actions.
Texte intégral:
Disponible
Indice:
WPRIM (Pacifique occidental)
Sujet Principal:
Encéphale
/
Cannabinoïdes
/
Transduction du signal
/
Système nerveux central
/
Morpholines
/
Rat Sprague-Dawley
/
Récepteur delta
/
Récepteurs aux opioïdes
/
Récepteur cannabinoïde de type CB1
/
Benzoxazines
Limites du sujet:
Animaux
langue:
Anglais
Texte intégral:
Korean Journal of Anesthesiology
Année:
2013
Type:
Article
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