Effects of diacetyl guan-fu base A on pacemaker cells in sinoatrial node of rabbits.
Abstract
AIM: To study the electrophysiological effects of diacetyl guan-fu base A (DGFA)
on pacemaker cells in sinoatrial (SA) node.
METHODS: Intracellular microelectrode method was used to record parameters of
action potential (AP) in SA node of rabbits.
RESULTS: DGFA could not only slow down spontaneous firing frequency (SFF), mean
rate of repolarization (MRR), and rate of diastolic depolarization (RDD), but
also prolong diastolic interval (DI) and duration of action potential (APD) in a
concentration-dependent manner in SA node. Furthermore, DGFA markedly decreased
the maximum rate of depolarization (MRD) with a slight reduce of the amplitude of
action potential (APA) and there was no significant effect on the maximal
diastolic potential (MDP). The decrease in SFF caused by DGFA was not affected by
atropine (0.05 mg/L).
CONCLUSION: The effects might be due to the reduction of calcium influx and
potassium efflux, and the muscarinic receptors were not involved.
Keywords:
on pacemaker cells in sinoatrial (SA) node.
METHODS: Intracellular microelectrode method was used to record parameters of
action potential (AP) in SA node of rabbits.
RESULTS: DGFA could not only slow down spontaneous firing frequency (SFF), mean
rate of repolarization (MRR), and rate of diastolic depolarization (RDD), but
also prolong diastolic interval (DI) and duration of action potential (APD) in a
concentration-dependent manner in SA node. Furthermore, DGFA markedly decreased
the maximum rate of depolarization (MRD) with a slight reduce of the amplitude of
action potential (APA) and there was no significant effect on the maximal
diastolic potential (MDP). The decrease in SFF caused by DGFA was not affected by
atropine (0.05 mg/L).
CONCLUSION: The effects might be due to the reduction of calcium influx and
potassium efflux, and the muscarinic receptors were not involved.