Fig. 6. Crustacean cardioactive peptide (CCAP) dose response. Anterior foregut contractions were elicited by delivering 5 ms pulses at 40 pulses s^–1 for 500 ms duration to the severed recurrent nerve. (A) An example of a movement transducer record from an early-molt larva initially in saline and then 10 min after exposure to 10^–8 mol l^–1 CCAP. (B) There is a strong dose–response relationship between the amount of contraction and increasing concentrations of CCAP. Plotted are the percentage increases in contraction amplitude elicited from stimulation of the recurrent nerve relative to the maximum response elicited in the initial saline conditions. Each point is an average of the responses of between five and 22 animals.