Reflexogenic neuronal and humoral responses to selective stimulation of low-pressure cardiopulmonary receptors in man.

Abstract

This study was conducted to determine the relative importance of efferent muscle sympathetic nerve activity (MSA), vasopressin (ADH) and atrial natriuretic peptide (ANP) in the short-term neurohumoral response to moderate changes in low-pressure cardiopulmonary receptor activity. The low-pressure receptors were stimulated and unloaded, respectively, by autotransfusion of blood (450 ml) and the application of lower body negative pressure (LBNP, -20 mmHg), and in 11 healthy men we measured MSA in the left peroneal nerve, indirect blood pressure, ECG, central venous pressure (CVP) and venous plasma concentrations of ANP and ADH (radioimmunoassay). Total MSA rose by 30% during LBNP and decreased during a rapid autotransfusion of blood, and the changes in MSA were significantly related to changes in CVP. The plasma concentrations of ADH and ANP were not significantly affected by either procedure. It is suggested that during moderate short-term changes in venous return, MSA responded more rapidly and/or at a lower threshold than the ADH and ANP systems.