The chemoreceptor molecules that mediate chemotactic responses in bacteria and archaea are physically clustered and operate as highly cooperative arrays. Few experimental approaches are able to investigate the structure-function organization of these chemoreceptor networks in living cells. This chapter describes chemical crosslinking methods that can be applied under normal physiological condit...

Nausea and vomiting are mediated primarily by three neurotransmitter pathways: visceral stimulation releases dopamine and serotonin; vestibular and central nervous system activation release histamine and acetylcholine; and chemoreceptor trigger zone activation releases dopamine and serotonin. Clinicians can improve the effectiveness and cost-effectiveness of treatments by targeting the appropri...

Escherichia coli cells use two distinct sensory circuits during chemotaxis towards carbohydrates. One circuit requires the phosphoenolpyruvate-dependent phosphotransferase system (PTS) and is independent of any specific chemoreceptor, whereas the other uses a chemoreceptor-dependent sensory mechanism analogous to that used during chemotaxis towards amino acids. Work on the carbohydrate chemotax...

The notion that intracellular Ca(2+) (Ca(i)(2+)) stores play a significant role in the chemoreception process in chemoreceptor cells of the carotid body (CB) appears in the literature in a recurrent manner. However, the structural identity of the Ca(2+) stores and their real significance in the function of chemoreceptor cells are unknown. To assess the functional significance of Ca(i)(2+) store...

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 o...

Chemoperception in invertebrates is mediated by a family of G-protein-coupled receptors (GPCR). To date nothing is known about the molecular mechanisms of chemoperception in coleopteran species. Recently the genome of Tribolium castaneum was sequenced for use as a model species for the Coleoptera. Using blast searches analyses of the T. castaneum genome with previously predicted amino acid sequ...

OBJECTIVES We investigated whether Angiotensin II (Ang II) modulates peripheral chemoreflex function through carotid body (CB) chemoreceptors in chronic heart failure (CHF). METHODS We measured renal sympathetic nerve activity (RSNA) in response to graded hypoxia before and after intravenous administration of Ang II (20 ng/kg/min, i.v. 30 min) or AT1 receptor antagonist (L-158,809, 0.33 mg/kg...

Chemoreceptor cells from rabbit carotid body (CB) exhibit transient outward currents reversibly inhibited by low P(o2). Molecular and functional dissection of the components of these outward currents indicates that at least two different channels (Kv4.3 and Kv3.4) contribute to this current. Furthermore, several lines of evidence support the conclusion that Kv4 channel subfamily members (either...

Hyperoxia in the immediate perinatal period, but not in adult life, is associated with a life-long impairment of the ventilatory response to acute hypoxia. This effect is attributed to a functional impairment of peripheral chemoreceptors, including a reduction in the number of chemoreceptor afferent fibers and a reduction in "whole nerve" afferent activity. The purpose of the present study was ...

Astrocytes provide structural and metabolic support for neuronal networks, but direct evidence demonstrating their active role in complex behaviors is limited. Central respiratory chemosensitivity is an essential mechanism that, via regulation of breathing, maintains constant levels of blood and brain pH and partial pressure of CO2. We found that astrocytes of the brainstem chemoreceptor areas ...