HTR1B and portal hypertension: [20]. Several clinical trials have confirmed the efficacy and favorable safety profile of this drug [21]. In addition to acting on cranial vessels, zolmitriptan also causes peripheral vasoconstriction in specific territories. Of particular interest when considering possible therapies for portal hypertension is the fact that 5HT1B/D receptors abound in human SMA where they mediate robust vasoconstrictive effects [6], [22].