Fig. 4: Activation of iGluRs excited the isolated rat atrial cardiomyocytes.

a Action potentials were evoked by the increasing injection currents from 5 pA to 125 pA by 5 pA step. The cells were separately treated with iGluR agonist puffs (1 mM glutamate, 1 mM AMPA or 1 mM NMDA, respectively), or the iGluR antagonists (100 μM CNQX, MK-801 or AP-5, respectively), which were delivered through the perfusion solution. Black arrows indicate the minimum threshold current evoking the action potential. b, c Pooled data of the minimum threshold current evoking action potential and the amplitude of the action potentials from a. *P < 0.05, calculated by Student’s t-test, n = 6 per group.