Abstract
Ischemia is associated with myocardial acidosis which recovers upon reperfusion. In such conditions, alpha 1-adrenergic stimulation is arrhythmogenic. We used single cardiac myocytes loaded with the pH fluorescent dye, SNARF-1, to determine if a modulation of pH could explain the effect of alpha 1-adrenergic stimulation. Cells were exposed to acidosis (CO2 15%) for 15 min and then normocapnia restored. During acidosis, alpha 1-adrenergic stimulation caused an increase in pH which was abolished by blocking Na+/H+ exchange with ethylisopropylamiloride (EIPA). After removal of acidosis aftercontractions were manifest in 8 out of 10 and 1 out of 5 cells in the presence of an alpha 1-adrenergic agonist and in control, respectively (p < 0.001). EIPA abolished the occurrence of after contractions. Thus, the arrhythmogenicity of alpha 1-adrenergic stimulation depends on activation of Na+/H+ exchanger.
| Translated title of the contribution | [Autom. eng. transl.] [The arrhythmogenicity of alpha 1-adrenergic stimulation following myocardial acidosis] |
|---|---|
| Original language | Italian |
| Pages (from-to) | 569-571 |
| Number of pages | 3 |
| Journal | Cardiologia |
| Volume | 37 |
| Publication status | Published - 1992 |
Keywords
- Acidosis
- Amiloride
- Animals
- Anti-Arrhythmia Agents
- Arrhythmias, Cardiac
- Benzopyrans
- Cardiomyopathies
- Fluorescence
- Fluorescent Dyes
- Heart
- Hydrogen-Ion Concentration
- Myocardial Contraction
- Rats
- Receptors, Adrenergic, alpha