Mitochondrial Reactive Oxygen Species Inactivate Neuronal Nicotinic Acetylcholine Receptors and Induce Long-Term Depression of Fast Nicotinic Synaptic Transmission

Abstract

Neuronal nicotinic acetylcholine receptors (nAChRs), ligand-gated ion channels implicated in a variety of cognitive, motor, and sensory behaviours, are targeted to compartments rich in mitochondria, particularly postsynaptic domains and presynaptic terminals, exposing these receptors to reactive oxygen species (ROS) generated by oxidative phosphorylation. In addition, these receptors can become exposed to ROS during the progression of certain neurodegenerative diseases. Because ROS are known to modify several membrane proteins, including some types of ion channels, it raises the question of whether elevations in cytosolic ROS alter the function of nAChRs. To address this, we elevated ROS in cultured sympathetic neurons, directly by perfusing neurons intracellularly with ROS, indirectly by blocking the mitochondrial electron transport chain, or noninvasively by transient NGF removal; we then simultaneously measured changes in cytosolic ROS levels and whole-cell ACh-evoked currents. In addition, we elevated cytosolic ROS in postganglionic neurons in intact ganglia and measured changes in nerve-evoked EPSPs. Our experiments indicate that mild elevations in cytosolic ROS, including that produced by transient interruption of NGF signaling, induce a use-dependent, long-lasting rundown of ACh-evoked currents on cultured sympathetic neurons and a long-lasting depression of fast nerve-evoked EPSPs. We show that these effects of cytosolic ROS are specific to nAChRs on neurons and do not cause rundown of ACh-evoked currents on muscle. Our results demonstrate that elevations in cytosolic ROS inactivate neuronal nAChRs in a use-dependent manner and suggest that mild oxidative stress impairs mechanisms mediated by cholinergic nicotinic signaling at neuronal-neuronal synapses.

Distribution and biomarkers of carbon‐14‐labeled fullerene C60 ([14C(U)]C60) in female rats and mice for up to 30 days after intravenous exposure

“…Endothelial cell malfunction is associated with decreased availability of nitric oxide, which in turn leads to increased generation of ROS. In nicotine signaling in cholinergic neurons, the present of reactive oxygen species (ROS) has been shown to inactivate nicotinic acetylcholine receptors on neurons (Campanucci, et al 2008, Krishnaswamy and Cooper 2012). The TCA cycle in the mitochondria is an essential metabolic pathway in all oxidative organism, and an interruption in TCA cycle can cause inefficient electron transfer resulting in generating toxic ROS (Mailloux, et al 2007).…”

A novel type of cells expressing GP2 in the respiratory epithelium of the paranasal sinuses in mice

“…Neuronal nicotinic acetylcholine receptors are targeted to compartments rich in mitochondria, such as presynaptic terminals and postsynaptic compartments. The elevated mitochondrial ROS, particularly during periods of strong electrical activity, modifies the function of neuronal acetylcholine receptors (2). Furthermore, mitochondrial Ca 2+ import plays a fundamental role in cell physiology through regulating cytoplasmic Ca 2+ signals and stimulating ATP production (3,13,15).…”

“…For single and double immunofluorescence staining, the sections were incubated with the rat anti-GP2 antibody overnight, followed by incubation with Alexa Fluor 488-labeled anti-rat IgG (Invitrogen, Carlsbad, CA) or Cy3-labeled anti-rat IgG (Jackson ImmunoResearch, West Grove, PA). The stained sections were further incubated with either guinea pig anti-human CGRPα antiserum (1 : 200, T-5027; Peninsula Laboratories Inc., San Carlos, CA), rabbit anti-substance P (1 : 1,000, Y151; Yanaihara Institute, Shizuoka, Japan), rabbit anti-human PGP9.5 antibody (1 : 2,000, RA-95101; Ultraclone, Isle of Wight, UK), or rabbit anti-Gα gust (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) antibody (1 : 1,800, sc-395; Santa Cruz Biotechnology, Inc., Santa Cruz, CA). The antigen-antibody reaction was visualized by incubation with Cy3-labeled anti-guinea pig IgG, Cy3-labeled anti-rabbit IgG (Jackson ImmunoResearch), or Alexa Fluor 488-labeled antirabbit IgG (Invitrogen).…”

A Highly Conserved Cytoplasmic Cysteine Residue in the α4 Nicotinic Acetylcholine Receptor Is Palmitoylated and Regulates Protein Expression

“…The authors propose that use-dependent inactivation of the ␣3␤4 nAChR occurs after the receptors have been repeatedly exposed to agonist over time due to mild elevations in reactive oxygen species (14,21,22). Receptor use can also enhance the depalmitoylation of proteins (23)(24)(25)(26)(27).…”