RESUMO
Objective To study the effects of the antiarrhythmic drugs of propafenone, amiodarone and dilthiazem on c-type Kv1. 4 channels in Xenopus laevis oocytes with two-electrode voltage-clamp technique. Methods Defolliculated oocytes ( stage Ⅴ - Ⅵ) had transcribed cRNAs of ferret Kv1. 4△N channels injected. The oocytes were continuously perfused with control solution or propafenone, amiodarone and dilthiazem under monitoring of software of Clampfit v 9. 0. Results All of the three drugs blocked ferret Kv1. 4△N channel in voltage-, frequency- and concentration-dependent manners. The values of IC50 (50%inhibiting concentration ) of propafenone, amiodarone and dilthiazem were ( 103.4± 2. 2 ) μ mol/L,(501.22 +5.9) μmol/L and (353.62 +9.9) μmol/L, respectively. The currents under the actions of propafenone , amiodarone and dilthiazem were decreased to 41%, 32% and 21% of control group, respectively. Propafenone (100μ mol/L), Amiodarone (500μmol/L), dilthiazem (350μmol/L) inhibited currents to (54. 6 + 1.9 ) %, ( 46. 3 + 3.5 ) %, ( 52. 8 ± 2. 8 ) % of control group in voltage-dependent blockage. Conclusions The results suggested that all the three drugs blocked the kv1. 4△N channel in the open state. The three drugs block the kv1. 4△N channel maybe had the similiar effects in some respects, but each had its unique characteristics.
RESUMO
The main pathological changes of hypoxia in the myocardium were lysis or necrosis of the myocardium.hyperplasia or swelling of myocardial mitochondria,and swelling.increase of pinocytic vesicles in number,and appearance of tubules and villus-like eminences in the endothelial cells of myocardial capillaries:And those in the lungs were thickening of the wall and narrowing of the lumen of pulmonary arterioles,and swelling or appearance of proteinous material in the connec- tive tissue around pulmonary venules.After the treatment with dilthiazem.the pathological lesions were decreased in number or diminished in severity.In addition,the pathological mechanisms of hy-poxia and the therapeutic efficacy of dilthiazem were discussed.
