Related Experiment Video
Updated: Aug 9, 2026
Determination of Mitochondrial Membrane Potential and Reactive Oxygen Species in Live Rat Cortical Neurons
Published on: May 23, 2011
Brain mitochondrial nitric oxide synthase: in vitro and in vivo inhibition by chlorpromazine
Silvia Lores-Arnaiz1, Gabriela D'Amico, Analía Czerniczyniec
1Laboratory of Free Radical Biology, School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina. slarnaiz@ffyb.uba.ar
Abstract:
Mouse brain mitochondria have a nitric oxide synthase (mtNOS) of 147 kDa that reacts with anti-nNOS antibodies and that shows an enzymatic activity of 0.31-0.48 nmol NO/min mg protein. Addition of chlorpromazine to brain submitochondrial membranes inhibited mtNOS activity (IC50 = 2.0 +/- 0.1 microM). Brain mitochondria isolated from chlorpromazine-treated mice (10 mg/kg, i.p.) show a marked (48%) inhibition of mtNOS activity and a markedly increased state 3 respiration (40 and 29% with malate-glutamate and succinate as substrates, respectively). Respiration of mitochondria isolated from control mice was 16% decreased by arginine and 56% increased by NNA (Nomega-nitro-L-arginine) indicating a regulatory activity of mtNOS and NO on mitochondrial respiration. Similarly, mitochondrial H2O2 production was 55% decreased by NNA. The effect of NNA on mitochondrial respiration and H2O2 production was significantly lower in chlorpromazine-added mitochondria and absent in mitochondria isolated from chlorpromazine-treated mice. Results indicate that chlorpromazine inhibits brain mtNOS activity in vitro and can exert the same action in vivo.
Insights
Chlorpromazine inhibits mouse brain mitochondrial nitric oxide synthase (mtNOS) activity. This inhibition enhances mitochondrial respiration and reduces hydrogen peroxide production, suggesting a key role for mtNOS in regulating mitochondrial function.
Area of Science:
- Biochemistry
- Neuroscience
- Mitochondrial Biology
Background:
- Mitochondria possess nitric oxide synthase (mtNOS) in the mouse brain.
- mtNOS activity is regulated and influences mitochondrial function.
Purpose of the Study:
- To investigate the effect of chlorpromazine on mouse brain mtNOS activity.
- To determine the impact of chlorpromazine-induced mtNOS inhibition on mitochondrial respiration and hydrogen peroxide production.
Main Methods:
- Enzymatic assays to measure mtNOS activity.
- Mitochondrial respiration studies using various substrates.
- Hydrogen peroxide (H2O2) production measurements.
- In vitro and in vivo administration of chlorpromazine and related compounds.
Main Results:
- Chlorpromazine directly inhibited mtNOS activity in vitro (IC50 = 2.0 microM).
- Mitochondria from chlorpromazine-treated mice showed 48% reduced mtNOS activity.
- Inhibition of mtNOS led to increased state 3 respiration and decreased H2O2 production.
- The regulatory effects of mtNOS on respiration and H2O2 were diminished by chlorpromazine.
Conclusions:
- Chlorpromazine effectively inhibits mouse brain mtNOS activity both in vitro and in vivo.
- mtNOS plays a regulatory role in mitochondrial respiration and H2O2 production.
- Chlorpromazine's effects on mitochondria are mediated, at least in part, by mtNOS inhibition.
More Related Videos
08:03Unveiling Xenobiotic Transport and Effects in Isolated Mitochondria: Insights from Respirometric and Enzymatic Assays
Published on: March 7, 2025
14:39Cholinergic Ligand–dependent Modulation of Oxidative Phosphorylation Coupling in Digitonin-permeabilized BE(2)-C Neuroblastoma Cells
Published on: April 28, 2026
