Reduction in cortical parvalbumin expression due to intermittent theta-burst stimulation correlates with maturation of the perineuronal nets in young rats.

摘要: We recently showed that intermittent theta-burst stimulation (iTBS) using transcranial magnetic strongly reduces the number of rat neocortical interneurons expressing glutamic acid decarboxylase 67 kDa (GAD67) and parvalbumin (PV), indicating changed activity fast-spiking (FS) interneurons. In advance in vitro studies intended to characterize changes electrical properties FS under these conditions, we tested whether iTBS effect is age-dependent. Conscious Sprague-Dawley rats aged between 28 90 days received three blocks at 15 min intervals. found iTBS-related reduction PV+ cells was absent up an age 32 days, then gradually increased, approached a maximum about 40% 40 days. The relative PV (PV+, 8-9%) did not change with sham-controls also increase cortical c-Fos expression induced by principally However, prominent growth perineuronal nets, typically surrounding cells, exactly paralleled effect. Based on findings, conclude functional development inhibitory network regard intracortical synaptic connectivity sufficiently matured younger than 35 d enable activity-dependent modifications during iTBS. Outgrowth nets associated maturation excitatory inputs, as characteristic for critical period, may take place before can be activated via repetitive stimulation, allowing plastic molecular phenotype likely plasticity.