Fig. 2. Effects of red pigment concentrating hormone (RPCH) on the isolated cardiac ganglion (CG). (A) Extracellular recording from the trunk during control (top trace) and in the presence of 10^–6 mol l^–1 RPCH (bottom trace). RPCH increased the burst frequency as well as the number of motor neuron spikes (large units). (B) Pooled data bar graphs showing significant increases in burst frequency, duty cycle, number of spikes per bursts and spike frequency in the burst induced by RPCH over control (C) values (Student's t-test; N=12; ^*P<0.05; ^**P<0.01).