Author/Editor		Arh, Maj; Budihna, Metka V
Title		Comparison of effects of nitrendipine, lacidipine and mibefradil on postischaemic myocardial damage in isolated rat hearts
Type		članek
Source		Pflugers Arch
Vol. and No.		Letnik 440, št. 5 Suppl
Publication year		2000
Volume		str. R149-50
Language		eng
Abstract		During ischaemia and reperfusion increased cytosolic Ca2+ is one of the important causes for ischaemic-reperfusion myocardial injury. In the present study we compared effects of preferentially L-type Ca2+ antagonists nitrendipine (NT) and lacidipine (LP), and of mibefradil (MB) a Ca2+ antagonist with higher affinity to T- than to L-type channels on myocardial function during reperfusion. Coronary flow (CF), heart rate (HR), left ventricular pressure (LVP), lactate dehydrogenase (LDH) release rate and ECG were registered during 40 min of reperfusion following 30 min of global zero flow ischaemia in Langendorff's isolated rat hearts. Either NT (100 nmol/L) or LP (10 nmol/L) or MB (100 nmol/L) was added to Krebs-Henseleit solution 10 min before ischaemia till the end of experiments. All three drugs influenced CP, HR and LVP. All of them decreased LDH release rate (P < 0.05, in micro kal/g.min) when compared with control hearts (53.2 +- 5.1): MB (19.4 +- 4.3) > LP (30 7 +- 6.6) > NT (43.3 +- 2.8). NT reduced the duration of continuous arrthythmias at the beginning of reperfusion (to 59.1 +- 6.1 % of ischaemic controls) as well as the number of single arrhythmic events arising during the whole period of reperfusion (to 26.1 +- 6.0 % of ischaemic controls). MB diminished only single arthythmic events during reperfusion to 39.1 +- 17.3 % of ischaemic controls. LP did not affect the onset of arrhythmias. Results of our experiments indicate a relatively greater importance of T-type than of L-type Ca2+ channels in the arising of postischaemic myocardial damage.
Descriptors		MYOCARDIAL REPERFUSION CALCIUM CHANNEL BLOCKERS HEART RATE VENTRICULAR PRESSURE ARRHYTHMIA RATS, WISTAR CORONARY CIRCULATION LACTATE DEHYDROGENASE