Invited Editorial NO and CO have got to GO for enhanced chemoreceptor sympathoexcitation in heart failure

ARTERIAL CHEMORECEPTORS LOCATED in the carotid body are an important defense mechanism against systemic hypoxemia. Activation of arterial chemoreceptors increases alveolar venti-lation and sympathetic outflow to most vascular beds. During acute exposures to hypoxia, the sympathoexcitatory responses to chemoreceptor activation are important in counteracting the direct vasodilator effects of hypoxemia and preventing falls in blood pressure that might compromise blood flow to hypoxic tissues. However, chronic activation of arterial chemoreceptors could conceivably lead to deleterious, chronic elevations in sympathetic outflow. The carotid body chemoreceptors have been shown to play an important role in the chronic sympa-thoexcitation observed in a rabbit cardiac pacing model of chronic heart failure (CHF) (13). Ding et al. (2) presen