H. V. Danylovych, Yu. V. Danylovych, T. V. Bohach,
V. T. Hurska, S. O. Kosterin

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: danylovych@biochem.kiev.ua

Received: 28 February 2019; Accepted: 17 May 2019

It was proved that NO synthesis in isolated mitochondria of rat uterus smooth muscle depended on the entry of exogenous Ca²⁺ to mitochondria (inhibited by 1-10 mM Mg²⁺ in the absence of ATP and by 10 μM ruthenium red) and was suppressed by calmodulin antagonists (0.1-10 μM calmidazolium and 1-100 μM trifluoperazine). It was blocked by N^G-nitro-L-arginine, a known antagonist of the constitutive NO-synthase, with a half-maximal inhibition effect at about 25 μM. Moderate deholesterinization of the plasma membrane of myocytes after processing with 0.01% digitonin was followed by increased nitric oxide biosynthesis by cells. The data obtained suggested that mitochondria and plasmalemma is a possible source of NO synthesis in uterine myocytes.