Fig. 5. Excitatory actions of proctolin and crustacean cardioactive peptide (CCAP) on the isolated cardiac ganglion (CG). (A) Intra-axonal recording from a motor neuron in control (top trace) and during 10^–6 mol l^–1 proctolin application (bottom trace). Note the increase in the slow wave form depolarization of the burst. (B) Pooled data showing significant effects of proctolin on burst frequency, duty cycle, number of spikes per burst and spike frequency in the burst (Student's t-test; N=8; ^*P<0.05; ^**P<0.01). (C) Same preparation after proctolin was washed out (top trace) and in 10^–6 mol l^–1 CCAP (bottom trace). CCAP increased the slow wave form depolarization of the motor neurons. (D) Pooled data showing significant effects of CCAP on burst frequency, duty cycle, number of spikes per burst and spike frequency in the burst (Student's t-test; N=8; ^*P<0.05; ^**P<0.01).