Entrainment of the Breathing Rhythm of the Carp by Imposed Oscillation of the Gill Arches

Artificial oscillation imposed onto the gill arches could modify the respiratory rhythm in the carp Cyprinus carpio. The degree of modification depended upon the frequency and amplitude of the applied movement. Oscillation at frequencies close to the spontaneous respiratory rhythm and at amplitudes in the range of 2-3 mm resulted in a cyclic pattern of lengthening and shortening of the breathing cycles. When the gill arches were maximally abducted artificially at the end of inspiration or early in expiration, the breathing cycle was shortened. A slight lengthening occurred when maximal gill arch abduction fell during the second half of expiration or during the first half of inspiration. An increase in oscillation amplitude led to entrainment of ventilation at a one-to-one ratio with the imposed movement. After oscillation stopped an aftereffect was seen. It is argued that gill arch proprioceptors contribute to the observed responses.