Organizing co mmittee

Conclusion / Application
. The scientific significance of the research results lies in 
the fact that the formation of a wide spectrum of antibiotics, more precisely 13,22-
dimethoxystachibotrin and stachibotral, was noted in the culture liquid by selected local 
strains of the fungi 
Stachybotrys chartarum
, the results obtained make a great 
contribution to the development of scientific research in our republic aimed at using 
environmentally fresh drugs. 
 
 

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Poster presentation 
221 
CHARACTERISTICS OF THE RELAXING ACTION OF 5-(4-
AMINOPHENYL)-1,3,4-OXADIAZOL-2(3H)-THIONE 
 
Yu.T. Mirzaeva
1
, D.S. Ismailova
2
, P.B. Usmanov
1
, B.J. Elmuradov
2
,
О.А Тursunova.
3
 
 
1) Institute of Biophysics and Biochemistry at the National University of Uzbekistan, 
Tashkent, Uzbekistan 
2) S.Yu. Yunusov Institute of the Chemistry of Plant Substances Academy of sciences of 
the Republic of Uzbekistan 
3) Andijan State University, Andijan, Uzbekistan 
*e-mail: [e-mail]
 
 
We have found that oxadiazole – D-111 exhibited marked vasorelaxant activity and 
significantly inhibited the contraction of rat aortic rings induced by KCl and 
phenylephrine (PE) study the effect of oxadiazole – D-111 action 5-(4-aminophenyl)-
1,3,4-oxadiazol-2(3H)-thione (D-111)) on the contractile activity of rat aortic smooth 
muscle cells (SMC). It is shown that the synthetic compound triazole-D-111 has a 
relaxing effect. 
In this regard, we carried out studies on the effect of oxadiazole -D-111 on the 
contractile activity of SMC of the rat aorta to establish the dependence of the relaxant 
activity of oxadiazole D-111 on its structure. The studies were carried out on the 
isolated preparations of the rat aorta, the contractile activity of the aorta was assessed in 
the isometric mode using a tension sensor (FT.03, Grass, USA) and a camera base. The 
experimental chamber was perfused with oxygenated carbogen (95% O
2
, 5% CO
2
) in 
the Krebs solution at a constant temperature of 37˚C. 
The relaxant effect of this triazole was dose-dependent, and with an increase in its 
concentration, the suppression degree of the contractions of aortic preparations induced 
by hyperpotassium solutions increased markedly. To further clarify the mechanism of 
action of oxadiazole, experiments were performed on the dependence of the relaxant 
effect of D-111 on the concentration (50-250 µM) of Ca
2+
ions in the incubation 
medium. In particular, in the presence of 250μM D-111, the addition of 2.5 mM CaCl2 
to the calcium-free solution caused a contraction of the aorta preparation, which was 
69,9±4,1% less than the contraction recorded in the absence of the oxadiazole. In these 
experiments, an increase in the concentration of CaCl
2
(0,5 mM- 2.5 mM) in the 
incubation medium was accompanied by a stepwise increase in the force of contraction 
of the aorta due to the penetration of Ca
2+
ions through the L-type Ca
2+
channels. 
The results of these experiments convincingly indicate that the relaxant effect of the 
test compound oxadiazole D-111 under conditions of KCl-induced contracture is 
associated with the suppression of the transport of Ca
2+
ions from the extracellular 
medium to the SMC cytoplasm through voltage-dependent Ca
2+
channels of the 
plasmalemma.