Ventilatory response to inspired CO 2 in the lizard, Tupinambis nigropunctatus

Abstract

1. 1. Elevating inspired levels of CO 2 (1–4%) in Tupinambis nigropunctatus leads to an increase in tidal volume, mean expiratory flow, mean inspiratory flow, duration of the non-ventilatory period, inspiratory duration, expiratory duration and end inspiratory lung volume. Minute ventilation is variable and end expiratory volume decreases. 2. 2. An increase or decrease in CO 2 concentration surrounding the head affects the duration of the non-ventilatory period before the altered CO 2 concentration is inspired into the lungs. 3. 3. The change in duration of the non-ventilatory period before altered CO 2 concentration is inspired into the lungs is probably mediated by CO 2 sensitive receptors located in the mouth, nose or on the head surface.