Figure 4: IPAN responses to applying PSA to mucosal epithelium.

(a,b) PSA concentration response plots (means±s.e.) were fitted with a logistic equation⁵⁵, IC₅₀ for sAHP AUC and g_leak were −7.0 and −6.7 log g ml⁻¹ respectively (n=28). (c) PSA (160 ng ml⁻¹) decreased AP firing threshold (*P=0.03, paired-Student’s t-test) and (d,e) increased the number of APs fired at twice threshold (P=0.03, Wilcoxon matched-pairs test). (f,g) RMP was depolarized (*P=0.03, paired-Student’s t-test) and g_leak decreased (*P=0.03, paired-Student’s t-test) by PSA. (h,i) PSA decreased sAHP (h) as measured by absolute AUC (i); also, AP_1/2w decreased (j) and the AP hump (k) and (l) the inflection (*) in the AP time derivative was reduced.