Mayer‐wave related oscillations (MWROs) are present in the vagal outflow during chemosensitive challenge

Abstract

The central coordination of respiratory and vasomotor functions is likely to be modulated by a diffuse neural network, providing a common rhythmical background, based on the interaction between respiratory and Mayer wave-related rhythms. While MWROs have been recently described in the brainstem respiratory network (Morris et al., 2010), evidence of the presence of this rhythm in vagal outflow is still lacking. In a decerebrate cat preparation, arterial blood pressure (BP), cervical sympathetic and vagal outflows were recorded at baseline (B) and during two stimuli: the injection of CO2-satured saline via vertebral artery (central chemoreceptor stimulation, CCS) and via carotid artery (peripheral chemoreceptor stimulation, PCS). BP and nerve activity signals were analyzed using a frequency domain approach, based on autoregressive spectral and cross-spectral analysis of heart rate (HR) variability. At baseline, low-frequency (LF, around 0.1 Hz, i.e., MWRO) and high-frequency (HF, synchronous with the respiratory rate) components were present in sympathetic and BP signals, while HR and vagal outflow showed only an HF component. Interestingly, a LF component was observed in vagal outflow during the PCS. These preliminary results support the hypothesis of a “common central oscillatory network” that promotes cardiorespiratory coupling. Supported by PRIN 2007 (NM) and NIH R37 NS019814 Grants.