Mg2+-induced adenosine-receptor mediated relaxations in mesenteric vascular beds of diabetic rats

Rok, strany: 2012, 409 - 413

Our previous studies showed that the magnesium Mg2+-induced relaxations were completely dependent on concentration of nitric oxide (NO) in non-diabetic rat mesenteric vascular beds, in diabetic rats other mechanisms may be involved. The present study was designed to determine the role of adenosine receptor in Mg2+-induced relaxation in streptozotocin (STZ)-induced diabetic rats vessels. Diabetes was induced by the intravenous injection of 60 mg/kg STZ. Eight weeks after diabetes induction, superior mesenteric arteries were isolated and perfused according to the McGregor method. Prepared vascular beds were constricted with phenylephrine to induce 70–75% of maximal constriction (0.001 M). Mg2+ at concentrations of 10^-4 to 10^-1 M were added into the medium and perfusion pressure was recorded. Theophylline (1 mM), and 3,7- dimethyl-1- propargylxanthine (0.01 μM) were added into medium 20 min before phenylephrine administration. In the presence of theophylline, vasorelaxation induced by high dose of Mg2+ (from 0.03 to 0.1 M) was totally suppressed. In presence of N(ω)-nitro-L-arginine methyl ester (L-NAME), the response of Mg2+ was completely inhibited at low dose of Mg2+. But, Mg2+-induced relaxation in the presence of adenosine A2a receptor blocker was significantly suppressed in high dose of Mg2+. Mg2+-induced relaxation in the presence of an A2a receptor blocker was not suppressed either by denudation of endothelium or presence of L-NAME. From the results of this study it may be concluded that Mg2+-induced relaxation at high concentrations is mediated by adenosine A2a receptors, but at low concentrations Mg2+-induced relaxation is dependent on NO.

ISO 690:

Tavasoli, R., Soltani, N., Keshavarz, M., Shorabipour, S. 2012. Mg2+-induced adenosine-receptor mediated relaxations in mesenteric vascular beds of diabetic rats. In General Physiology and Biophysics, vol. 31, no.4, pp. 409-413. 0231-5882.

APA:

Tavasoli, R., Soltani, N., Keshavarz, M., Shorabipour, S. (2012). Mg2+-induced adenosine-receptor mediated relaxations in mesenteric vascular beds of diabetic rats. General Physiology and Biophysics, 31(4), 409-413. 0231-5882.