Fig. 4.

Changes to synaptic transmission received by S neurons of the submucosal plexus. A: change in the paired-pulse ratio (PPR) in controls and inflamed animals. B: representative PPR recording from a control neuron (top), and a neuron from a 28-day TNBS-treated animal (bottom). Scale bars: 5 mV, 20 ms. C: magnitude of the slow excitatory postsynaptic action potential (EPSP) received by VIP-expressing S neurons (S-VIP neurons) from control and inflamed animals. D: representative traces of reduced slow EPSP magnitude from S-VIP neurons. The recording demonstrates the prominent inhibitory postsynaptic action potentials received by these neurons. Large long-lasting slow EPSPs are received by control neurons (I), which occasionally reach AP threshold (spikes on trace). Downward deflections on traces reflect current injections used to monitor input resistance during the EPSP. Slow EPSP magnitude is reduced at 3 (II), 7 (III), and 28 (IV) days. Scale bars: 10 mV, 5 s. Solid circles in B and D indicate the stimulus artifact. *P < 0.05.