TRPA1 and TRPV1 are required for lidocaine-evoked calcium influx and neuropeptide release but not cytotoxicity in mouse sensory neurons

• Published in: PloS one 2017-11, Vol.12 (11), p.e0188008
• Main Authors: Eberhardt, Mirjam, Stueber, Thomas, de la Roche, Jeanne, Herzog, Christine, Leffler, Andreas, Reeh, Peter W, Kistner, Katrin
• Format: Article
• Language: English
• Subjects: Anesthesia; Anesthesiology; Anesthetics; Apoptosis; Biology and Life Sciences; Calcitonin; Calcitonin gene-related peptide; Calcium; Calcium (intracellular); Calcium channels; Calcium imaging; Calcium influx; Calcium mobilization; Calcium permeability; Capsaicin receptors; Cell culture; Cell death; Critical care; Cytotoxicity; Dorsal root ganglia; Endoplasmic reticulum; Enzyme-linked immunosorbent assay; Excitability; Inflammation; Intracellular; Ion channels; Irritation; Kinases; Laboratories; Lidocaine; Medical schools; Medicine; Medicine and Health Sciences; Mice; Mortality; Nerves; Neurons; Neuropeptides; Neurotoxicity; Pain; Peripheral nerves; Physiological aspects; Physiology; Receptors; Research and Analysis Methods; Rodents; Sensory neurons; Sodium channels; Sodium channels (voltage-gated); Stores; Studies; Toxicity
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0188008

Local anaesthetics (LA) reduce neuronal excitability by inhibiting voltage-gated Na+ channels. When applied at high concentrations in the direct vicinity of nerves, LAs can also induce relevant irritation and neurotoxicity via mechanisms involving an increase of intracellular Ca2+. In the present study we explored the role of the Ca2+-permeable ion channels TRPA1 and TRPV1 for lidocaine-induced Ca2+-influx, neuropeptide release and neurotoxicity in mouse sensory neurons. Cultured dorsal root ganglion (DRG) neurons from wildtype and mutant mice lacking TRPV1, TRPA1 or both channels were explored by means of calcium imaging, whole-cell patch clamp recordings and trypan blue staining for cell death. Release of calcitonin gene-related peptide (CGRP) from isolated mouse peripheral nerves was determined with ELISA. Lidocaine up to 10 mM induced a concentration-dependent reversible increase in intracellular Ca2+ in DRG neurons from wildtype and mutant mice lacking one of the two receptors, but not in neurons lacking both TRPA1 and TRPV1. 30 mM lidocaine also released Ca2+ from intracellular stores, presumably from the endoplasmic reticulum. While 10 mM lidocaine evoked an axonal CGRP release requiring expression of either TRPA1 or TRPV1, CGRP release induced by 30 mM lidocaine again mobilized internal Ca2+ stores. Lidocaine-evoked cell death required neither TRPV1 nor TRPA1. Depending on the concentration, lidocaine employs TRPV1, TRPA1 and intracellular Ca2+ stores to induce a Ca2+-dependent release of the neuropeptide CGRP. Lidocaine-evoked cell death does not seem to require Ca2+ influx through TRPV1 or TRPV1.