Effect of Sigma Receptor Ligand Haloperidol in Guinea Pig Heart
| Authors | |
|---|---|
| Year of publication | 2004 |
| Type | Article in Periodical |
| Magazine / Source | Acta Veterinaria Brunensis |
| MU Faculty or unit | |
| Citation | |
| Field | Physiology |
| Keywords | cardiac sigma receptor; contractility; mechanical restitution; desensitisation |
| Description | Sigma receptors represent a group of enigmatic binding sites with many functions in different tissues. In rat heart, they are responsible for modulation of cardiac contractility. They are also responsible for some adverse side effects of certain psychotropic drugs on cardiovascular system. In this study, the effect of sigma receptor ligand haloperidol on guinea pig heart multicellular preparations was studied. Its positive inotropic effect previously described in rat cardiomyocytes was confirmed in left atria and papillary muscles isolated from the right ventricles (an increase of the twitch amplitude by 36% to 123% in comparison with the control period in atria and by 9% to 46% in ventricular preparations; all values were statistically significant when compared to control in atrial preparations, but only in the first five min of perfusion in papillary muscles). Also desensitisation process previously reported in rat myocardium after repeated exposure to haloperidol was confirmed (although not statistically significant). The normalized course of mechanical restitution curve was not changed during perfusion with haloperidol. It is concluded that its positive inotropic effect is very likely mediated via increased cytosolic availability of calcium. |
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