Nattie E, Li A. Central chemoreception in wakefulness and sleep: evidence for a distributed network and a role for orexin. J Appl Physiol 108: 1417–1424, 2010. First published February 4, 2010; doi:10.1152/japplphysiol.01261.2009.—This minireview examines data showing the locations of central chemoreceptor sites as identified by the presence of ventilatory responses to focal, mild acidification...

Evidence from human and animal studies suggests that the arterial chemoreflex may be exaggerated in essential hypertension. In the present study, cardiorespiratory responses to peripheral chemoreceptor stimulation were compared in conscious unrestrained spontaneously hypertensive (SH) and normotensive Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats (13-14 wk old). Chemoreceptors were stimulated...

Adjustments of respiration and circulation in response to alterations in the levels of oxygen, carbon dioxide and hydrogen ions in the body fluids are mediated by two distinct chemoreceptive elements, situated peripherally and centrally. The peripheral arterial chemoreceptors, located in the carotid and aortic bodies, are supplied with sensory fibres coursing in the sinus and aortic nerves, and...

We used 2',7'-bis(carboxyethyl)-5(6)-carboxyflourescein (BCECF), a pH-sensitive fluorescent dye, to study intracellular pH (pH(i)) regulation in neurons in CO(2) chemoreceptor and nonchemoreceptor regions in the pulmonate, terrestrial snail, Helix aspersa. We studied pH(i) during hypercapnic acidosis, after ammonia prepulse, and during isohydric hypercapnia. In all treatment conditions, pH(i) f...

The aim of the present work was to elucidate the role of NADPH oxidase in hypoxia sensing and transduction in the carotid body (CB) chemoreceptor cells. We have studied the effects of several inhibitors of NADPH oxidase on the normoxic and hypoxia-induced release of [3H]catecholamines (CA) in an in vitro preparation of intact CB of the rat and rabbit whose CA deposits have been labeled by prior...

Crayfish depend on sensilla, small cuticular structures occurring all over their bodies to acquire information about their outside environment. Sensilla contain sensory neurons that are either mechanoreceptive or chemoreceptive. The tail fan of crayfish houses numerous sensilla that contain mechanoreceptor neurons and their activation by animals approaching from behind elicits a tail-flip escap...

Background Exogenous adenosine has been shown to increase muscle sympathetic nerve activity (MSNA), blood pressure, heart rate, and ventilation in conscious humans, effects attributed to peripheral chemoreceptor activation. Methods and Results To determine whether endogenous adenosine has similar effects and whether they are mediated through chemoreceptor activation, we examined the effects of ...

The brainstem network for generating and modulating the respiratory motor pattern includes neurons of the medullary ventrolateral respiratory column (VRC), dorsolateral pons (PRG) and raphé nuclei. Midline raphé neurons are proposed to be elements of a distributed brainstem system of central chemoreceptors, as well as modulators of central chemoreceptors at other sites, including the retrotrape...

Superoxide anion is the most important reactive oxygen species (ROS) primarily generated in cells. The main cellular constituents with capabilities to generate superoxide anion are NADPH oxidases and mitochondrial respiratory chain. The emphasis of our article is centered in critically examining hypotheses proposing that ROS generated by NADPH oxidase and mitochondria are key elements in O(2)-s...

During chemotaxis toward asparagine by Bacillus subtilis, the ligand is thought to bind to the chemoreceptor McpB on the exterior of the cell and induce a conformational change. This change affects the degree of phosphorylation of the CheA kinase bound to the cytoplasmic region of the receptor. Until recently, the sensing domains of the B. subtilis receptors were thought to be structurally simi...