Figure 1: Hemidissection preparation and responses of IPANs to adding JB-1 or TRAM-34 to epithelial and myenteric compartments.
(a) Patch clamp recordings were made from IPANs (AH cells) in the myenteric compartment; control Krebs or bacteria are applied to epithelium in a separately perfused compartment positioned circumferentially from the myenteric compartment. (b) Firing thresholds decreased after adding JB-1 (**P=0.008, paired-Student’s t-test). (c,d) Number of APs fired during test current pulse was increased by JB-1, in example recording (c) upper to lower trace and (d) summary data (**P=0.01, Wilcoxon matched-pairs test). (e,f) JB-1 depolarized IPANs (**P=0.01, paired-Student’s t-test) and decreased leak conductances (***P=0.001, paired-Student’s t-test). (g,h) Post-AP sAHP was reduced by JB-1, example trace in (g) and summary in (h) (**P=0.008, paired-Student’s t-test). (i) JB-1 reduced AP1/2w (**P=0.008, paired-Student’s t-test) and this AP narrowing was accompanied by a decrease in the AP hump (j) or inflection (*) on the AP time derivative (k). (l) Adding 10 mM TEA.Cl to the myenteric compartment widened the AP and the hump; subsequent addition of JB-1 to the epithelial compartment significantly reversed the action of TEA (n=5). (m) IPAN exposed to TRAM-34 for 12 min increased the number of APs discharged during a 500-ms test stimulus. The depolarizing stimulus current pulse intensity was 2 × the initial threshold, which was 40 pA for this neuron.
