Endogenous activation of metabotropic glutamate receptors in neocortical development causes neuronal calcium oscillations

Oscillations in intracellular free calcium concentration ([Ca2+](i)) occur spontaneously in immature neurons of the developing cerebral cortex. Here, we show that developing murine cortical neurons exhibit calcium oscillation s in response to direct activation of the mGluR5 subtype of the group I met abotropic glutamate receptor (mGluR). In contrast, other manipulations that elicit [Ca2+](i) increases produce simple, nonoscillatory changes. Further more, we find that spontaneous oscillatory [Ca2+](i) activity is blocked by antagonists of group I mGluRs, suggesting a specific role for mGluR activa tion in the promotion of oscillatory [Ca2+](i) dynamics in immature cortica l neurons. The oscillatory pattern of [Ca2+](i) increases produced by mGluR activation might play a role in the regulation of gene expression and the control of developmental events.