Publication details
Antipsychotic Haloperidol as a Ligand of Sigma Receptors and its Cardiotoxicity
| Authors | |
|---|---|
| Year of publication | 2007 |
| Type | Article in Proceedings |
| Conference | Morphology 2007 |
| MU Faculty or unit | |
| Citation | |
| Keywords | sigma receptor;haloperidol;myocardium;cardiotoxicity;rat;guinea pig |
| Description | The Sigma receptors were indentified in many tissues include a cardiac tissue. At first they were members of opioid receptors family. Later they were reclassified, due to their ability to bind ligands of nonopioid character. The point of this study was to investigate submicroscopic and physiologic changes of cardiomyocytes, throughout acute effect of haloperidol (H). For this study we chose two rats and two guinea pigs. One of each group as a control (C) and one as an experimental (E) animal. The animals were of male sex, because it is highly possible, that the endogenous ligand of sigma receptors is progesterone. It could interfere with H, and therefore induce false positivity. The animals were sacrificed by cervical dislocation in ether narcosis. We put out their hearts immediately and put them into the Langendorff apparatus. Simultaneously we scaned an elektrocardiogram (ECG). At first each heart was perfused by Krebs-Henseleit solution (KHS) for 30 minutes, then washed the C by KHS , the E by H at the concentration of 10 nM for 30 minutes. Afterwards we washed out the hearts by KHS. Finaly was perfused by 3% solution of glutaraldehyde for 10 minutes. The hearts were cut in strips 1x1x3 mm from both atria and both ventricles. Cardiac tissue was processed for electron microscopy by standard procedure. The electronmicrographs showed, that the ultrastructure of C was normal. In E, there were damages of Z discs. The mitochondria were elongated, many of them were swollen and rounded. We can not leave out of consideration the agglomeration of mitochondria. We observed the increased amount of mitochondrial corpuscles. The diads were widened. ECG results in C accounted no pathology. In E, we could see alterations immediately after the perfusion of H. The QT interval was elongated followed by retarding of the heart rate. Then the ventricular arrythmias were discovered, both the free and the fixed arrythmias. Analogous to other studies H is considered to be toxic, too. The reason of ECG pathology is perhaps caused by the activity of H at kalium channels. But some changes we can not explain this way. It is possible, that the dilatation of diads and anomalies at mitochondria manipulate the calcium (Ca2+) homeostasis. This homeostasis is important in heart action, too. |