Effects of prolonged inflation on pulmonary stretch receptor discharge in turtles.

摘要: The tonic and phasic discharge characteristics of single, slowly adapting pulmonary stretch receptors (SAR) were examined before after 1 h periods constant pressure inflation to normal resting (VLr, = 0 cm H2O) elevated (VLe, 10 lung volumes in turtles (Chrysemys sp.). Based on their at VLr, SAR classified as either low (n 13) or high threshold 4) receptors. Inflations performed with both air 5% CO2 air. Lung gas composition arterial PCO2 pH measured during the maintained inflations. In animals ventilated air, adapted by 57 30% respectively over first 3 min VLe. During remainder period, fell an additional 20% while that remained relatively constant. There significant increases alveolar Ventilation reduced static levels 25% respectively, suggesting a part apparent adaptation these for was due accumulation metabolic CO2. Following inflation, responses pump ventilation decreased but unchanged SAR. associated step receptor groups. data suggest increased is sustained indefinitely volume may account persistent changes breathing pattern previously observed chronic volume.