Generation of Ca²⁺ signals in an astrocyte.

<p>We consider astrocytic compartments which consist of three parts: the intracellular space, the internal Ca²⁺ store (endoplasmatic reticulum) and the extracellular space. Ca²⁺ signals in the intracellular space are generated by two different pathways: the metabotropic glutamate receptor (mGluR)-dependent pathway and the glutamate transporter (GluT)-dependent pathway. The mGluR-dependent pathway describes the glutamate dependent production of IP₃, which then evokes IP₃ and Ca²⁺ dependent exchange of Ca²⁺ between the intracellular space and the endoplasmatic reticulum. The GluT-dependent pathway describes the GluT driven transport of Ca²⁺ between the extracellular and the intracellular space.