Possible Interaction: Methysergide and Yohimbine

“The contraction was blocked by the 5-HT(1,2) receptor antagonist methysergide and was markedly reduced by the 5-HT(2B) receptor antagonist, yohimbine , which also profoundly affected 5-HT induced contractions in fundic strips.”

“ Methysergide and metergoline did not change the seizure threshold alone, but both of them antagonized the anticonvulsant effect of yohimbine.”

“Intrathecal pretreatment with yohimbine and methysergide produced a significantly greater increase in the number of flinches than in the control in phase 1, intermediate period and phase 2.”

“Posttreatment with yohimbine and methysergide showed a significantly greater increase in the number of flinches in phase 2.”

“pretreatment with methysergide; the coadministration of methysergide with yohimbine produced no greater antagonism of effects.”

“4 The 5‐hydroxytryptamine (5‐HT) receptor ligands, 8‐hydroxy‐2‐(di‐n‐propylamino)‐tetralin (8‐OH‐DPAT), RU 24969, and methysergide inhibited the binding of [3H]‐yohimbine to rat cortex with high and low affinity, consistent with an interaction with two populations of binding sites.”

“This response to yohimbine (3 X 10(-7) M) was attenuated by 5-HT receptor antagonists such as 5-methoxygramine, methysergide and ketanserin.”

“When coadministered intrathecally, methysergide and yohimbine antagonized the increases in TFL and PWT produced by stimulation of NRM and of NRPG sites.”

“ Methysergide , a serotonergic antagonist, significantly reduced yohimbine- and 5-HT-induced vasoconstriction but failed to influence the effect of noradrenaline.”