TLDR Brain-made chemicals can control nerve cell function differently in various parts of a mouse's brain, which may help us understand neurological conditions.
The 2020 study "Nucleus‐specific modulation of phasic and tonic inhibition by endogenous neurosteroidogenesis in the murine thalamus" investigated the role of neurosteroids, brain-synthesized chemicals, in modulating phasic and tonic inhibition in different areas of the mouse brain. The researchers used 20 mice and applied finasteride, a 5α-reductase inhibitor, to block neurosteroidogenesis. They found that in the thalamic reticular nucleus (nRT), finasteride altered the decay and amplitude of phasic currents but didn't affect tonic inhibition. However, in ventrobasal nucleus (VB) neurons, finasteride reduced both the size and frequency of phasic currents and the degree of tonic inhibition. This suggests that neurosteroids can modulate GABAAR function in a nucleus-specific manner, which could have implications for understanding neurological conditions.
97 citations
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December 2010 in “Journal of Neuroscience” Midazolam impairs learning and memory by increasing neurosteroids through specific receptor activation.
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April 1992 in “Journal of Biological Chemistry” Four-amino acid part makes enzyme sensitive to finasteride.
November 2019 in “Synapse” Brain-made chemicals can control nerve cell function differently in various parts of a mouse's brain, which may help us understand neurological conditions.
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September 2013 in “The International Journal of Neuropsychopharmacology” 
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December 2012 in “Epilepsia” Neurosteroids change how GABA_A receptors work in the brain, which could be important for treating temporal lobe epilepsy.
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June 2011 in “Alcoholism: Clinical and Experimental Research” Three drugs change mice's alcohol drinking patterns by affecting GABAA receptors.
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January 2008 in “Biological & Pharmaceutical Bulletin” Finasteride almost fully depletes allopregnanolone in rat brains and enhances 20α-DHP, but doesn't change 3α-DHP levels.
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April 2007 in “European Journal of Pharmacology” 
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April 2007 in “Neuroscience” Finasteride reduces alcohol withdrawal severity in male mice but increases it in female mice.
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November 2006 in “Pharmacology, Biochemistry and Behavior” Pregnancy reduces anxiety in rats, but finasteride reverses this effect.
