Respiratory arrhythmias in the Port Jackson shark, Heterodontus portusjacksoni

Abstract

1. 1. Respiratory arrhythmias, including Cheyne-Stokes respiration occurred in undisturbed, normoxic Port Jackson sharks, Heterodontus portusjacksoni. 2. 2. “Eupnoeic” ventilation replaced arrhythmias after mechanical manipulations, anaesthesia or surgery. 3. 3. Arrhythmias were reversibly abolished by an increase in p ICO 2 or a decrease in p IO 2. 4. 4. It is suggested that a central neural slow rhythm generator manifest under conditions of minimal respiratory demand can modulate the output of the respiratory centres.