Fig. 3.
Na+ contributed to membrane potential. A: in current clamp (I = 0), a reduction in external Na+ from 135 mM to 5 mM (130 mM NMDG) induced hyperpolarization in human colonic SMC (n = 4). B: pretreatment with TEA (1 mM) and apamin (300 nM) gradually decreased spontaneous transient hyperpolarization. Addition of NMDG in the presence of TEA and apamin also caused hyperpolarization. C and D: similar effect of Na+ replacement with NMDG was recorded in monkey colonic SMC in the absence (C) and presence (D) of TEA and apamin (n = 4).
