High resolution

Module 10: Figure neocortical Ca2+ release

Role of inositol 1,4,5-trisphosphate receptors (InsP3Rs) and the ryanodine receptors (RYRs) in presynaptic transmitter release.

Metabotropic glutamate receptors produce inositol 1,4,5-trisphosphate (InsP3), which releases Ca2+ from a presynaptic store to trigger neurotransmitter release. Ryanodine receptors (RYRs) may amplify this signal, since they can also be induced to release Ca2+ through a process of Ca2+-induced Ca2+ release (CICR). The Ca2+ that activates these RYRs can come either from the InsP3Rs or from Ca2+ entering through the voltage-dependent Ca2+ channels (VDCCs). Reproduced from Simkus, C.R.L. and Stricker, C. (2002) The contribution of intracellular calcium stores to mEPSCs recorded in layer II neurones of rat barrel cortex. J. Physiol. 545:521–535, with permission from Blackwell Publishing; see Simkus and Stricker 2002.