A conserved peptide-binding pocket in HyNaC/ASIC ion channels.

The only known peptide-gated ion channels-FaNaCs/WaNaCs and HyNaCs-belong to different clades of the DEG/ENaC family. FaNaCs are activated by the short neuropeptide FMRFamide, and HyNaCs by Hydra RFamides, which are not evolutionarily related to FMRFamide. The FMRFamide-binding site in FaNaCs was recently identified in a cleft atop the large extracellular domain.

Dynorphin Neuropeptides Decrease Apparent Proton Affinity of ASIC1a by Occluding the Acidic Pocket.

Prolonged acidosis, as it occurs during ischemic stroke, induces neuronal death via acid-sensing ion channel 1a (ASIC1a). Concomitantly, it desensitizes ASIC1a, highlighting the pathophysiological significance of modulators of ASIC1a acid sensitivity. One such modulator is the opioid neuropeptide big dynorphin (Big Dyn) which binds to ASIC1a and enhances its activity during prolonged acidosis.

Efficient expression of a cnidarian peptide-gated ion channel in mammalian cells.

Hydra Na channels (HyNaCs) are peptide-gated ion channels of the DEG/ENaC gene family that are directly activated by neuropeptides of the nervous system. They have previously been successfully characterized in oocytes. To establish their expression in mammalian cells, we transiently expressed heteromeric HyNaC2/3/5 in human HEK 293 and monkey COS-7 cells.

Validation of activity questionnaires in patients with cystic fibrosis by accelerometry and cycle ergometry.

Background: The objective of this study was to validate physical activity questionnaires for cystic fibrosis (CF) against accelerometry and cycle ergometry.

Methods: 41 patients with CF (12-42 years) completed the Habitual Activity Estimation Scale (HAES), the 7-Day Physical Activity Recall questionnaire (7D-PAR) and the Lipid Research Clinics questionnaire (LRC) and performed an incremental exercise test according to the Godfrey protocol up to volitional fatigue. Time spent in moderate and vigorous physical activity (MVPA) assessed objectively by accelerometry was related to the time spent in the respective activity categories by correlation analyses and calculating intraclass correlation coefficients (ICC).