Avian arterial chemoreceptor responses to steps of CO 2 and O 2

• Published in: Respiration physiology Vol. 90; no. 3; pp. 325 - 340
• Main Authors: Hempleman, S.C., Powell, F.L., Prisk, G.K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1992
• Subjects: Birds, duck; Carotid body, sensitivity CO 2, O 2 steps; Control of breathing, arterial chemoreceptors; Receptors, arterial chemo; Receptors, arterial chemo; Carotid body, sensitivity CO 2, O 2 steps; Control of breathing, arterial chemoreceptors; Birds, duck
• ISSN: 0034-5687
• DOI: 10.1016/0034-5687(92)90112-A

The responses of avian arterial chemoreceptor preparations to 44-sec steps of inspired CO 2 and O 2 were quantified. Anesthetized ducks were unidirectionally ventilated, arterial pH was recorded with a fast responding indwelling electrode, and neural activity was recorded from 28 preparations consisting of dissected filaments of the vagus nerve (23 single-fibered, 5 few-fibered). We analyzed responses using cycle-triggered stimulus histograms of neural discharge, cross correlation analysis, and analysis of variance. Average responses of the chemoreceptor preparations to Pa CO 2 steps from 24 ± 1 to 38 ± 1 Torr were larger (per 56 ± 2 Torr. Average responses to CO 2 steps usually appeared more rate sensitive when measured during arterial hypoxia than during arterial normoxia. These characteristics are very much like those reported for mammalian arterial chemoreceptors, except that responses of avian chemoreceptor preparations to repetitive CO 2 steps were highly variable according to statistical analysis.