Changes induced by estradiol-ethylenediamine derivative on perfusion pressure and coronary resistance in isolated rat heart: L-type calcium channel.

Aim: The present study was designed to investigate the effects of estradiol-ethylenediamine derivative on perfusion pressure and coronary resistance in rats. An additional aim was to identify the molecular mechanisms involved.

Methods: The Langendorff model was used to measure perfusion pressure and coronary resistance changes in isolated rat heart after estradiol-ethylenediamine derivative alone and following compounds; tamoxifen (estrogen receptor antagonist), prazosin (alpha1 adrenoreceptor antagonist), metoprolol (selective beta1 receptor blocker), indomethacin (prostanglandin synthesis inhibitor) and nifedipine (L-type calcium-channel inhibitor).

Results: The results show that estradiol-ethylenediamine derivative [10(-9) mmol] significantly increased perfusion pressure (p = 0.005) and coronary resistance (p = 0.006) in isolated rat heart. Additionally, the effect of estradiolethylenediamine on perfusion pressure [10(-9) to 10(-4) mmol] was only blocked in the presence of the L-type calcium-channel (nifedipine).

Conclusions: These data suggest that the effect of estradiol-ethylenediamine on perfusion pressure and vascular coronary involves activation of the L-type calcium channel through a non-genomic molecular mechanism.