Slow Ca²⁺ oscillations caused by release from intracellular stores have been observed in neurons in the lamprey spinal cord. These oscillations are triggered by activation of metabotropic glutamate receptors on the cell surface. The pathway leading from receptor activation to the inositol triphosphate-mediated release of Ca²⁺ from the endoplasmatic reticulum has been modelled in order to facilitate further understanding of the nature of these oscillations. The model generates Ca²⁺ oscillations with a frequency range of 0.01–0.09 Hz. A prediction of the model is that the frequency will increase with a stronger extracellular glutamate signal.