Neurosteroids Involved in Regulating Inhibition in the Inferior Colliculus

The study investigated the role of 3α,5α-reduced neurosteroids in regulating inhibitory efficacy in the auditory midbrain of anesthetized rats. By blocking the GABAergic projection from the dorsal nucleus of the lateral lemniscus (DNLL) to the contralateral central nucleus of the inferior colliculus (ICC), researchers observed a compensatory increase in the efficacy of other inhibitory circuits in the ICC. This effect was prevented by inhibiting neurosteroid synthesis with finasteride, indicating that neurosteroids play a crucial role in maintaining the balance of excitatory and inhibitory inputs when GABAergic inhibition is reduced. Immunohistochemistry confirmed increased neurosteroid levels in the ICC following DNLL blockade, highlighting the brain's ability to rapidly adjust neurosteroid synthesis to maintain neural circuit balance.