Retinoids inhibit bradykinin B1 receptor-sensitized responses in human umbilical vein

Bradykinin B1 receptors are not expressed under physiological conditions but are induced under inflammatory conditions. In isolated human umbilical vein, a spontaneous bradykinin B1 receptor sensitization process has been demonstrated. On the other hand, retinoids have been shown to exert anti-inflammatory and immunomodulatory actions. We have now examined the effects of all-trans-retinoic acid and 9-cis-retinoic acid on the bradykinin B1 receptor-sensitized responses in human umbilical vein. Both retinoids produced a concentration-dependent rightward shift of the concentration-response curves for the bradykinin B1 receptor agonist, des-Arg(9)-bradykinin. Retinoid treatment did not modify the responses to bradykinin B1 receptor-unrelated agonists, bradykinin or serotonin. In conclusion, retinoids inhibit bradykinin B1 receptor-sensitized responses and this action could participate in their anti-inflammatory and immunomodulatory effects.