Optogenetically Controlled Activity Pattern Determines Survival Rate of Developing Neocortical Neurons.

A substantial proportion of neurons undergoes programmed cell death (apoptosis) during early development. This process is attenuated by increased levels of neuronal activity and enhanced by suppression of activity. To uncover whether the mere level of activity or also the temporal structure of electrical activity affects neuronal death rates, we optogenetically controlled spontaneous activity of synaptically-isolated neurons in developing cortical cultures.

Coincident Activation of Glutamate Receptors Enhances GABA Receptor-Induced Ionic Plasticity of the Intracellular Cl-Concentration in Dissociated Neuronal Cultures.

Massive activation of γ-amino butyric acid A (GABA) receptors during pathophysiological activity induces an increase in the intracellular Cl-concentration ([Cl]), which is sufficient to render GABAergic responses excitatory. However, to what extent physiological levels of GABAergic activity can influence [Cl] is not known. Aim of the present study is to reveal whether moderate activation of GABA receptors mediates functionally relevant [Cl] changes and whether these changes can be augmented by coincident glutamatergic activity.

Allopregnanolone augments epileptiform activity of an in-vitro mouse hippocampal preparation in the first postnatal week.

In the immature brain the neurotransmitter γ-amino butyric acid (GABA) mediates a membrane depolarization and can contribute to both, inhibition and excitation. Therefore the consequences of a positive modulation of GABA(A) receptors by neurosteroids on epileptiform activity are hard to predict. In order to analyze whether neurosteroids attenuate or exaggerate epileptiform activity in the immature brain, we investigated the effect of the neurosteroid allopregnanolone on epileptiform activity in an in-toto hippocampus preparation of early postnatal mice (postnatal days 4-7) using field potential recordings.