Key Points
- To characterize swelling-activated chloride currents in guinea pig atrial and ventricular myocytes and compare their electrophysiological and pharmacological profiles to isoprenaline-activated chloride currents.
- Conducted whole-cell patch-clamp recordings on isolated guinea pig atrial and ventricular myocytes.
- Assessed channel conductivity, anion selectivity, and sensitivity to blockers (tamoxifen, 4,4'-diisothiocyano-stilbene-2,2'-disulphonate, and anthracene-9-carboxylic acid) under osmotic swelling or isoprenaline exposure.
- Swelling-activated chloride currents exhibited outward rectification and sensitivity to blockers (tamoxifen > DIDS > 9-AC), occurring in >90% of atrial myocytes and 34% of ventricular myocytes.
- Isoprenaline-activated currents showed reduced iodide conductance and were entirely insensitive to the three blockers, appearing in >90% of ventricular myocytes and <10% of atrial myocytes.
- Co-activated currents in single ventricular myocytes retained their independent electrophysiological and pharmacological characteristics without mutual exclusivity.
Structured PICO
PPopulationGuinea pig atrial and ventricular myocytes
IInterventionOsmotic swelling and isoprenaline application
OOutcomeElectrophysiological and pharmacological properties of chloride currentssurrogate
Guinea pig atrial and ventricular myocytes preferentially express distinct chloride channels (swelling-activated vs. isoprenaline-activated) with unique electrophysiological and pharmacological profiles.