title: Long-term monitoring of Ca2+ dynamics in C. elegans pharynx: an in vivo energy balance sensor.
abstract: Ca2+ is a key signal transducer for muscle contraction. Continuous in vivo monitoring of intracellular Ca2+-dynamics in C. elegans pharynx muscle revealed surprisingly complex Ca2+ patterns. Despite the age-dependent decline of pharynx pumping, we observed unaltered fast Ca2+ oscillations both in young and old worms. In addition, sporadic prolonged Ca2+ increases lasting many seconds or minutes were often observed in between periods of fast Ca2+ oscillations. We attribute them to the inhibition of ATP-dependent Ca2+-pumps upon energy depletion. Accordingly, food deprivation largely augmented the frequency of prolonged [Ca2+] increases. However, paradoxically, prolonged [Ca2+] increases were more frequently observed in young worms than in older ones, and less frequently observed in energy-deficient mitochondrial respiratory chain nuo-6 mutants than in wild-type controls. We hypothesize that young animals are more susceptible to energy depletion due to their faster energy consumption rate, while nuo-6 mutants may keep better the energy balance by slowing energy consumption. Our data therefore suggest that the metabolic state of the pharynx during feeding stimulation depends mainly on the delicate balance between the instant rates of energy production and consumption. Thus, in vivo monitoring of muscle Ca2+ dynamics can be used as a novel tool to study cellular energy availability.
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Alvarez-Illera
authors.affiliation: Department of Biology, University of Hartford, West Hartford, Connecticut, USA.
authors.forename: Adolfo
authors.initials: A
authors.lastname: Sanchez-Blanco
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Lopez-Burillo
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain.
authors.forename: Rosalba I
authors.initials: RI
authors.lastname: Fonteriz
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Alvarez
authors.affiliation: Department of Biochemistry and Molecular Biology and Physiology, Institute of Biology and Molecular Genetics, Faculty of Medicine, University of Valladolid and CSIC, Ramón y Cajal, Valladolid, Spain.
authors.forename: Mayte
authors.initials: M
authors.lastname: Montero
mesh_terms: D000367:Age Factors; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004734:Energy Metabolism; D005247:Feeding Behavior; D009119:Muscle Contraction; D009154:Mutation; D010609:Pharyngeal Muscles / Q000378:metabolism; D010614:Pharynx / Q000378:metabolism*; D013997:Time Factors
chemical_list: D002118:Calcium
keywords: C. elegans; Gerotarget; aging; calcium; energy balance; pharynx