[Effect of substance K on the contractility of cardiomyocytes].

Aim: To investigate the influence and the mechanism of SK on the contractility of cultured cardiomyocytes of rats.

Methods: The primary cultured single myocardial cell was treated with SK and the contraction frequency and size of cardiomyocyte were determined by a computer image analysis system. At the same time the effects of propranolol (a beta receptor antagonist), phentolamine (a alpha receptor antagonist), DSP (a tachykinin receptor antagonist) on the action of SK were investigated.

Results: SK increased contractive extend of the cardiomyocyte, in which a dose-response relationship of SK at 1.78 x 10(-8) - 1.78 x 10(-5) mol/L exists. But the frequency of contraction did not change, pretreatment with propranolol, phentolamine had no action on the effect of SK, but DSP markedly attenuated the effects of SK.

Conclusion: SK may directly enhance the contractility of single cardiomyocyte, which may be related with the tachykinin receptor.