NEUROTROPHINS AND ACTIVITY-DEPENDENT PLASTICITY OF CORTICAL INTERNEURONS

Neocortical and hippocampal GABA-containing interneurons are susceptib le to activity-dependent modulation, such as regulation of soma size, numbers of synaptic, contacts, and levels of GABA or neuropeptide expr ession, In vitro, the effects of neuronal activity on morphology and g ene expression of GABA-containing neurons are mimicked, in part, by me mbers of the neurotrophin gene family, such as brain-derived neurotrop hic factor (BDNF), in the neocortex and hippocampus, BDNF is synthesiz ed and secreted in an activity-dependent manner by pyramidal neurons, the target cells of GABA-containing neurons, suggesting that BDNF is a n activity-dependent, target-derived trophic factor for these interneu rons, In support of this, neuronal activity fails to upregulate the ex pression of neuropeptide Y in hippocampal cultures from BDNF-deficient mice, We, therefore, hypothesize that neurotrophins might mediate som e of the actions of neuronal activity on GABA-containing neurons.