Key Points
- Investigate the ionic currents and the effects of acetylcholine on isolated guinea-pig atrial cells.
- Patch-clamp technique used for whole-cell recordings
- Voltage-clamp experiments assessed various ionic currents
- Dose-response evaluation of acetylcholine effects on membrane potential and currents
- Acetylcholine significantly shortened action potential duration in a dose-dependent manner (max effect at 10(-6) M)
- K+ currents increased with ACh administration, showing progressive deactivation with a time constant of 111 +/- 16 ms
- ACh influenced Ca2+ current reduction, which remained insignificant in Cs+-loaded cells at 10(-7) M ACh
Structured PICO
PPopulationIsolated single atrial cells of the guinea-pig heart
IInterventionAcetylcholine (ACh) at doses ranging from 10(-9) M to 10(-5) M
CComparatorControl (baseline/absence of ACh)
OOutcomeMembrane potential and ionic currents (Ca2+ current, inward and outward rectifying K+ currents)surrogate
In guinea-pig atrial cells, acetylcholine predominantly activates a K+ conductance, which can confound the measurement of its effects on calcium currents.