V.F. Kirichuk - Dr.Sc. (Med.), Professor, Head of Department of Normal Physiology named after I.A. Chuevsky, Saratov State Medical University named after V.I. Razumovsky. E-mail: aa-tsymbal@yandex.ru
A.A. Tsymbal - Ph.D. (Med.), Associate Professor, Department of Normal Physiology named after I.A. Chuevsky, Saratov State Medical University named after V.I. Razumovsky