Regional neurovasomotor reactions of pulmonary circulation

In experiments on anaesthetized cats with intact chest regional blood volume and flow in the lungs at horizontal and vertical body positions and under vagus and sympathetic nerve stimulation were studied using regional lung electroplethysmography. The regions of the lungs bearing more significant hydrostatic and hemodynamic load turn more labile to neurogen stimuli. The parasympathetic vasomotor reaction of the basal lung regions increases while the apical region reaction decreases at a vertical body position. The results obtained suggest the occurrence of regionally differentiated mechanisms of vasomotor control in the pulmonary circulation, directed to compensation of postural changes in pulmonary hemodynamics.