Possible Interaction: Guanfacine and Yohimbine

“Atomoxetine and guanfacine reduced premature responses, while yohimbine bi-phasically affected this index of motor impulsivity.”

“These effects of guanfacine were blocked by co-administered yohimbine , a non-selective α(2)-AR antagonist.”

“Yohimbine treatment during early withdrawal increased reinstatement to conditioned cues, while guanfacine treatment reduced reinstatement to yohimbine.”

“Consistently, bath-application of guanfacine suppressed eEPSC in layer V/VI pyramidal neurons, and this effect was blocked by the alpha2-AR antagonist yohimbine or the Gi inhibitor NF023.”

“ Yohimbine (0.1 microM), a nonspecific alpha(2)-adrenoceptor antagonist caused a parallel shift to the right (1.2 log unit) in the concentration-response curve of guanfacine without depressing the maxima.”

“That noradrenaline was approximately 10 fold more potent than dopamine, that the dopamine response was not antagonised … (-)sulpiride, but was mimicked by the α2-agonist guanfacine and partially antagonised by the α2-adrenoceptor antagonist yohimbine (which … guanfacine ) would indicate that a component of … is effected via α2-adrenoceptor mechanisms.”

“The antikinesic action of guanfacine was antagonised completely by yohimbine (1 mg/kg), but not prazosin (1 mg/kg).”

“Naloxone (0.1 mg/kg) does not change, whereas prazosin and yohimbine (both on doses of 0.1 mg/kg) remove and partly relieve the depressant effect of guanfacine.”

“The effects of guanfacin were antagonized by idazoxan, yohimbine and RX821002 (all selective for alpha 2-adrenoceptors) but not prazosin (selective for alpha 1-adrenoceptors).”

“The inhibitory effect of clonidine and guanfacine was antagonized by yohimbine.”