Negative modulation of the GABAAρ1 receptor function by histamine
Andrea N Beltrán González1, Manuel I López Pazos1, Mariana Del Vas2
1Laboratorio de Neurobiología Celular y Molecular, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIByNE), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad de Buenos Aires (UBA), Ciudad Autónoma de Buenos Aires, Argentina.
European Journal of Pharmacology
|July 5, 2023
Summary
Histamine, a neurotransmitter, was found to inhibit GABAAρ1 receptors, unlike its known modulatory effects on other GABAA subtypes. This study reveals a novel inhibitory action of histamine on ionotropic GABA receptors.
Area of Science:
- Neuroscience
- Pharmacology
- Molecular Biology
Background:
- Histamine acts as a neurotransmitter and neuromodulator, classically through G protein-coupled receptors.
- Histamine is known to positively modulate various GABAA receptor subtypes.
- The effect of histamine on GABAAρ1 receptors, crucial for retinal neuron tonic currents, was previously unexamined.
Purpose of the Study:
- To investigate the effects of histamine on human homomeric GABAAρ1 receptor function.
- To determine if histamine modulates GABAAρ1 receptors and characterize the nature of this interaction.
Main Methods:
- Heterologous expression of human GABAAρ1 receptors in Xenopus laevis oocytes.
- Electrophysiological recording of GABA-evoked chloride currents.
- Concentration-response analysis in the presence and absence of histamine.
Main Results:
- Histamine inhibited GABAAρ1 receptor-mediated currents.
- The inhibition was reversible, membrane potential-independent, and dependent on histamine and GABA concentrations.
- A parallel rightward shift in the GABA concentration-response curve indicated competitive antagonism.
Conclusions:
- Histamine competitively antagonizes human GABAAρ1 receptors.
- This represents the first report of histamine exerting inhibitory actions on an ionotropic GABA receptor.
- These findings uncover a novel inhibitory role for histamine in neuronal signaling, particularly in retinal pathways.
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