Unilateral Chronic Ischemia of the Carotid Bodies Alters Sympathetic Nervous System Activity

Abstract

As is well known, activation of carotid body chemoreceptors that sense arterial blood oxygen can lead to sympathetic nervous system (SNS) activation, while chronic hypoxia-induced activation of the carotid bodies promotes the development of various cardiovascular diseases. It has been shown in the literature that bilateral activation of the carotid bodies reduces chronotropic baroreflex sensitivity, which is restored following their subsequent bilateral ablation. In this work, we demonstrate that unilateral chronic ischemization of the rat carotid bodies by ligation of the external carotid artery decreases chronotropic baroreflex sensitivity, whereas unilateral ablation of the carotid bodies, on the contrary, increases it. At the systemic level, the reduction in SNS activity is further confirmed by a decrease in the glucose level. Our results show that even unilateral hyperactivation or inactivation of the carotid bodies induce systemic alterations in SNS activity.