9316434 Furilla Blood passing through the lungs of air-breathing animals picks up oxygen and eliminates carbon dioxide on inspiration when fresh air enters the lung, but not on expiration. This process leads to rhythmic oscillations in the level of oxygen and carbon dioxide in the blood leaving the lungs. Recently, a relationship was shown between these oscillations and respiration in mammals. Moreover, the rate at which carbon dioxide rises may be an adequate stimulus in controlling breathing frequency. These oscillations are not only influenced by breathing, but are also altered by the state of activity (e.g. exercise). Therefore, it is the purpose of this study to examine the role of lung and blood gas oscillations on the control of breathing in birds and reptiles. These studies are possible because birds and snakes (unlike mammals) have lungs that are open at both ends, making it possible to pass air through the lung in one direction only. Oxygen and carbon dioxide will then be made to oscillate in the airstream. The effect of these oscillations on nerves that respond to these gases will be recorded. In another series of experiments, the effect of the oscillations on breathing will be examined. A computer will monitor breathing and control gas mixing; therefore, the animal can control the gas mixer with its breathing movements, thereby controlling its blood gases. The contribution of nerves monitoring lung and blood gases as well as interactions between these nerves and the central nervous system will be examined. This information will provide insight into the influence of these dynamic processes in air-breathing animals, including mammals. ***
