Is Aberrant Reno-Renal Reflex Control of Blood Pressure a Contributor to Chronic Intermittent Hypoxia-Induced Hypertension?

This study demonstrated unaltered vascular conductance in response to lumbar sympathetic stimulation in CIH-exposed rats. Aortic compliance was increased and estimated blood volume was unchanged in CIH-exposed rats. Increased blood pressure was related to an increase in cardiac output, which was confirmed by echocardiography (Lucking et al., 2014). It is suggested therefore that hypertension in the CIH model can be evoked by over-excitation of the cardiac arm of sympathetic nervous system (SNS), even before mechanisms of enhanced peripheral vasoconstriction and endothelial dysfunction are initiated (Naghshin et al., 2009). This may have less relevance to human OSAS where increased cardiac output is not typically observed. Indeed, cardiac fibrosis, inflammation and apoptosis were reported in CIH-exposed animals, revealing long-term deleterious outcomes for the CIH-exposed heart (Wei et al., 2016). Carotid Body Response to CIH Disturbances in the autonomic nervous system alter cardiac output and vascular tone, which can result in blood pressure elevation. This raises the issue of the cause of autonomic disturbance in CIH models and OSAS. It is possible that the carotid bodies and kidneys play a role in driving sympathoexcitation. Both organs are sensitive to modest decreases in the partial pressure of oxygen (Patinha et al., 2017) and are innervated by afferent nerves that project to hindbrain regions, which play a key role in modulating sympathetic outflow (Johns et al., 201...
Source: Frontiers in Physiology - Category: Physiology Source Type: research