The results showed that PKC activity was enhanced by 48% (Fig. 1c, P = 0.003), meanwhile, pERK expression was increased by 70% in the PMA group than in the Met group (Fig. 2f, P = 0.010), further demonstrating that ERK is a downstream signaling molecule of PKC and that metformin regulates the expression of atrial SK2 and SK3 in T2DM rats via the PKC/ERK signaling pathway. Here, KCNN2 is linked to type 2 diabetes mellitus.