Further studies on the anti-nociceptive effect of vasopressin

The possible interactions of pathways which mediate anti-nociception when stimulated by alpha 2-adrenoceptor agonists and arginine vasopressin (AVP) were investigated. Yohimbine, an alpha 2-antagonist, failed to modify the anti-nociceptive response of AVP. However, clonidine pretreatment, in sub-effective and effective doses, potentiated the anti-nociceptive response of a sub-effective dose of AVP. This potentiation was attenuated by yohimbine and completely antagonized by naloxone. These studies suggest that pathways related to the opioidergic system and those stimulated by alpha 2-agonists may be utilized by AVP in eliciting the anti-nociceptive response.