The effects of hypoxia and CO sub(2) on the sleep-waking pattern of the potoroo (Potorous tridactylus apicalis)

Four male potoroos (P. t. apicalis ) breathed 21% and 7% O sub(2) with and without the addition of 5% CO sub(2). The effects of these gas mixtures on the potoroo's sleeping-waking pattern (SWP) were studied. The SWP while breathing 21% O sub(2)/5%CO sub(2) was unchanged when compared with that of breathing ambient air (21% O sub(2)). While breathing 7% O sub(2), the SWP was severely disrupted: total sleep time (TST) and slow wave sleep (SWS) increased markedly. Brain temperature fell substantially. Paradoxical sleep (PS) was almost abolished and wakefulness (W) decreased. The addition of 5% CO sub(2) to the O sub(2) deficient gas mixture, i.e., 7% O sub(2)/5% CO sub(2), restored the SWP to that obtained while breathing ambient air. It is concluded that CO sub(2) neutralizes the disruptive effect which hypoxia has on the potoroo's SWP.