CYSTATHIONINE GAMMA-LYASE AS A REGULATOR OF RESISTANCE ARTERY CONTRACTION UNDER NORMAL AND HYPERGLYCEMIC CONDITIONS

EMILOVA, R., D. DIMITROVA, V. GEORGIEV, T. DANEVA and H. S. GAGOV, 2013. Cystathionine gamma–lyase as a regulator of resistance artery contraction under normal and hyperglycemic conditions. Bulg. J. Agric. Sci., Supplement 2, 19: 175–177 The aim of our study is to clarify the contribution of cystathionine gamma–lyase (CSE) that produces H 2 S in smooth muscle and perivascular adipose tissues in the regulation of resistance size rat artery contraction. In this research the isometric contraction of de-endothelised rat gracilis artery preparations was measured with Small Vessel Myograph (DMT 410M, Denmark). Half of the isolated rings were incubated in 20 mmol/l D-glucose-containing bath and the others in normal glucose solution (5.5 mmol/l). Increasing concentrations of serotonin (5-hydroxytryptamine) from 10 –10 to 10 –5 mmol/l were applied to induce gradual constriction of circular artery segments. The absence of endothelium was confi rmed by the lack of the relaxation to acetylcholine. The extra cellular glucose concentration of 20 mmol/l did not infl uence the contractile effect of serotonin. The inhibition of CSE by DL-propargyl glycine signifi cantly enhanced the maximal force of serotonin-induced contraction under normal and hyperglycemic conditions. It is concluded that CSE is an important regulator of endothelium denuded rat resistance arteries. It is suggested that CSE in smooth muscle cells of artery wall released mediator that antagonized the constricting action of serotonin. This regulation is insensitive to extra cellular glucose concentration.