Melatonin decreases neuronal excitability in a sub-population of dorsal root ganglion neurons.

Abstract

Melatonin, a powerful antioxidant, participates in the regulation of important physiological and pathological processes. We investigated the actions of melatonin on neuronal excitability of intact dorsal root ganglions (DRG) from rats using intracellular recording techniques in current clamps. Melatonin blocked the generation of action potentials in a concentration-dependent manner. Bath applied melatonin (1.0-1000.0 nM) hyperpolarized the resting membrane potential, and increased the input resistance and rheobase. Melatonin also altered the active electrophysiological properties of the action potential, amplitude and maximum descendant inclination, in a statistically significant way. In order to provide evidence on the mechanism of action of melatonin in the DRG, quantitative PCR (qPCR) was performed. Analyses were performed for melatonin membrane receptors, MT1 and MT2, and it was observed that the DRG expresses MT1 receptors. In addition, we noted that the melatonin-induced effects were blocked in the presence of luzindole, a melatonin receptor antagonist. The minimal effective concentrations of melatonin (10.0 nM) and the blockade of effects caused by luzindole suggest that the effects of melatonin are hormonal, and are induced when it binds to MT1 receptors.

• Authors: Klausen Oliveira-Abreu, Francisco Walber Ferreira-da-Silva, Kerly Shamyra da Silva-Alves, Nathalia Maria Silva-Dos-Santos, Ana Carolina Cardoso-Teixeira, Fernanda Gaspar do Amaral, José Cipolla-Neto, José Henrique Leal-Cardoso
• Journal: Brain research (Brain Res) Vol. 1692 Pg. 1-8 (08 01 2018) ISSN: 1872-6240 [Electronic] Netherlands
• PMID: 29702086 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2018 Elsevier B.V. All rights reserved.

Chemical References

• Antioxidants
• RNA, Messenger
• Receptor, Melatonin, MT1
• Receptor, Melatonin, MT2
• Ribosomal Proteins
• Rpl37a protein, rat
• Melatonin

Topics

• Animals
• Antioxidants (pharmacology)
• Electric Stimulation
• Ganglia, Spinal (cytology)
• Gene Expression (drug effects)
• Male
• Melatonin (pharmacology)
• Membrane Potentials (drug effects)
• Neurons (classification, drug effects)
• Patch-Clamp Techniques
• RNA, Messenger (metabolism)
• Rats
• Rats, Wistar
• Receptor, Melatonin, MT1 (genetics, metabolism)
• Receptor, Melatonin, MT2 (genetics, metabolism)
• Ribosomal Proteins (genetics, metabolism)