Cell experiment:

The rat aorta is placed in Krebs solution and stripped of connective tissue, then subsequently cut into rings (2 to 3 mm in length). As indicated, the endothelium is removed by rubbing the intimal surface of rings with a pair of forceps. The rings are suspended in organ baths containing oxygenated (95% O2 and 5% CO2) Krebs bicarbonate solution. Following equilibration for 90 min under a resting tension of 2 g, the rings are contracted with KCl (80 mM) to assess their reactivity. After a 30-min washout period, the rings are contracted with the α1-adrenergic receptor agonist phenylephrine (10-6 M) to about 80% of the maximal contraction before addition of acetylcholine (10-6 M) to check for the presence of a functional endothelium. After a 30-min equilibration period, the rings with or without endothelium are exposed to Urapidil (10-5 M) for 25 min before inducing a concentration-contraction curve to phenylephrine[1].

Urapidil HCl is an α1-adrenoceptor antagonist and 5-HT1A receptor agonist.Target: α1-adrenoceptor; 5-HT1A receptorUrapidil hydrochloride is a hydrochloride salt form of urapidil which is α1-adrenoceptor antagonist and 5-HT1A receptor agonist with pIC50 of 6.13 and 6.4 respectively. Urapidil has an alpha-blocking effect but, unlike other alpha-blockers, also has a central sympatholytic effect mediated via stimulation of serotonin 5HT1A receptors in the central nervous system [1]. Urapidil has an alpha-blocking effect but, unlike other alpha-blockers, also has a central sympatholytic effect mediated via stimulation of serotonin 5HT1A receptors in the central nervous system. Several studies have suggested that oral urapidil is effective and well tolerated when used as second-line therapy in patients with BP inadequately controlled with other agents. Urapidil has also been shown to improve glucose and lipid metabolism in hypertensive patients with concomitant diabetes and/or hyperlipidemia [2].

References:
[1]. Gross, G., G. Hanft, and N. Kolassa, Urapidil and some analogues with hypotensive properties show high affinities for 5-hydroxytryptamine (5-HT) binding sites of the 5-HT1A subtype and for alpha 1-adrenoceptor binding sites. Naunyn Schmiedebergs Arch Pharmacol, 1987. 336(6): p. 597-601.
[2]. Buch, J., Urapidil, a dual-acting antihypertensive agent: Current usage considerations. Adv Ther, 2010. 27(7): p. 426-43.