Figure 5. The cardiovascular effects of hypoxic isocapnic blood stimulation of the vascularly isolated perfused carotid bodies and of superimposition of distension of the bladder in artificially ventilated cervical vagosympathectomized animals with open pneumothorax.

Neuromuscular blockade. Bladder distension pressure, 48·4 ± 3·1 mmHg (±s.d.); volume, 9·9 ± 4·2 ml (kg body wt)⁻¹ (±s.d.). Carotid sinus perfusion pressure was maintained constant. Left-hand panels: •, stimulation of the carotid bodies at zero bladder pressure; ^, superimposition of distension of the bladder at different levels of P_O2 of the carotid body perfusate. Right-hand panels: ▴, difference between the control (normoxic blood) and experimental (hypoxic blood) values during stimulation of the carotid bodies; ▵, change in variable resulting from distension of the bladder at each level of carotid body perfusate P_O2. Values are means ±s.e.m. for sixteen series of observations in eight animals. Arrowed filled circles with horizontal bars are the mean values ±s.e.m. for the P_O2 of the carotid body perfusate. Where no s.e.m. bar is given, the s.e.m. is smaller than the size of the symbol. Abbreviations and symbols as in Fig. 2.