Midaglizole hydrochloride (DG5128) is a preferential α2-adrenoceptor antagonist. Midaglizole hydrochloride (DG5128) exhibits 7.4 times higher affinity (pKi=6.28) toward α2-adrenoceptor than α1-adrenoceptor.
Midaglizole (DG-5128) at concentrations up to 10 μM inhibits [3H]clonidine binding more effectively than it doed [3H]prazosin binding in rat cerebral cortex membranes. The mode of inhibition is homogeneous and consistent with the law of simple mass action[1]. The EC50 values for stimulation of insulin release from rat islets and the MIN6 β-cell line induced by Midaglizole are 200 nM and 24 μM, respectively. The IC50 values for KATP current inhibition induced by Midaglizole are 3.8 μM and 4.4 uM for Kir6.2 and Kir6.2/SUR1 , respectively[2].
Midaglizole (3 and 30 mg/kg, i.v.) increases blood pressure in pithed rats[3].
[1]. Yamanaka K, et al. The selectivity of DG-5128 as an alpha 2-adrenoceptor antagonist. Eur J Pharmacol. 1984 Nov 27;106(3):625-8. [2]. Proks P, et al. Inhibition of recombinant K(ATP) channels by the antidiabetic agents midaglizole, LY397364 and LY389382. Eur J Pharmacol. 2002 Sep 27;452(1):11-9. [3]. Hirohashi M, et al. Intrinsic pressor activity of midaglizole, an alpha-2 adrenoceptor antagonist, in pithed rats. Jpn J Pharmacol. 1990 Aug;53(4):519-20.