The glycine receptor alpha 3 subunit mRNA expression shows sex-dependent differences in the adult mouse brain

Abstract

Background The glycinergic system plays an important inhibitory role in the mouse central nervous system, where glycine controls the excitability of spinal itch- and pain-mediating neurons. Impairments of the glycine receptors can cause motor and sensory deficits. Glycine exerts inhibition through interaction with ligand-gated ion channels composed of alpha and beta subunits. We have investigated the mRNA expression of the glycine receptor alpha 3 (Glra3) subunit in the nervous system as well as in several peripheral organs of female and male mice. Results Single-cell RNA sequencing (scRNA-seq) data analysis on the Zeisel et al. (2018) dataset indicated widespread but low expression of Glra3 in vesicular glutamate transporter 2 (Vglut2, Slc17a6) positive and vesicular inhibitory amino acid transporter (Viaat, Slc32a1)positive neurons of the mouse central nervous system. Highest occurrence of Glra3 expression was identified in the cortex, amygdala, and striatal regions, as well as in the hypothalamus, brainstem and spinal cord. Bulk quantitative real-time-PCR (qRT-PCR) analysis demonstrated Glra3 expression in cortex, amygdala, striatum, hypothalamus, thalamus, pituitary gland, hippocampus, cerebellum, brainstem, and spinal cord. Additionally, male mice expressed higher levels of Glra3 in all investigated brain areas compared with female mice. Lastly, RNAscope spatially validated Glra3 expression in the areas indicated by the single-cell and bulk analyses. Moreover, RNAscope analysis confirmed co-localization of Glra3 with Slc17a6 or Slc32a1 in the central nervous system areas suggested from the single-cell data. Conclusions Glra3 expression is low but widespread in the mouse central nervous system. Clear sex-dependent differences have been identified, indicating higher levels of Glra3 in several telencephalic and diencephalic areas, as well as in cerebellum and brainstem, in male mice compared with female mice.

Spinal Glycine Receptor Alpha 3 Cells Communicate Sensations of Chemical Itch in Hairy Skin

“…The latter study is more consistent with our observations as the Glra3 -Cre(+) populations were localized in both the dorsal and ventral laminae ( Fig. 1 A–C ), which is also in agreement with mRNA expression of Glra3 ( Ceder et al, 2023 ). To investigate the dendritic localization of Glra3 -Cre(+) neurons, we performed cell fillings ( Fig.…”

“…Additionally, starter, lineage, and virally labeled Glra3 -Cre(+) cells were observed in the ventral horn. In line with these observations, we recently showed that Glra3 is detected in the dorsal and ventral horns of the lumbar division ( Ceder et al, 2023 ). Thus, it remains unclear whether sensory-mediating Glra3 -Cre(+) neurons receive motor input or if the ventrally located Glra3 -Cre population have motor functions.…”

“…Glycinergic receptors (GLRs) are ligand-gated ion channels, which induce inward hyperpolarizing chloride currents upon binding of glycine ( Lynch, 2004 ; Zeilhofer, 2005 ; Lein et al, 2007 ; Dutertre et al, 2012 ). In mice, the glycine receptor alpha 3 ( Glra3 ) gene is expressed in both excitatory and inhibitory spinal dorsal horn neuronal clusters ( Häring et al, 2018 ; Zeisel et al, 2018 ; Ceder et al, 2023 ) and GLRA3 immunoreactivity is detected in the dorsal ( Harvey et al, 2004 ; Wang et al, 2018 ; Werynska et al, 2021 ) and ventral horns of the spinal cord ( Harvey et al, 2004 ; Wang et al, 2018 ). The other Glr genes, Glra1 , Glra2 , Glra4 , and Glrb , are also expressed in the dorsal horn of the spinal cord ( Groemer et al, 2022 ).…”

Structural Basis for Molecular Recognition of Cannabinoids by Inhibitory Cys-Loop Channels

“…Conversely, agonist binding to inhibitory channels GlyR and GABA A R induces an inward flow of chloride anions into the cell, provoking membrane potential hyperpolarization and decreased cellular excitability . While the expression patterns of GlyRs and GABA A Rs exhibit some overlap and emerging evidence suggests that GlyRs are ubiquitously expressed in several areas in the central nervous system (CNS), GABA A Rs are generally described as the primary mediators of inhibitory signals within the brain, whereas GlyRs would act predominantly in the spinal cord and brainstem, regulating a variety of motor and sensory functions . Their regulatory role in the CNS combined with the structural diversity of their modulators (several of which, including benzodiazepines, neurosteroids, cannabinoids, and volatile anesthetics, are currently used to treat psychiatric and neurological disorders such as anxiety, schizophrenia, epilepsy, and chronic pain) − make these receptors highly exploitable targets for therapeutic intervention.…”