The calcium ion (Ca²⁺) is a universal and versatile signal transduction molecule, and plays a prominent role of defining the cellular state. There are many types of metabotropic receptors contributing to intracellular Ca²⁺ signaling. Metabotropic glutamate receptors (mGluRs) expressing abundantly in striatum also related to the Ca²⁺ signaling and are thought to be related to Parkinson's disease. However, it is not clear that the character of the Ca²⁺ signaling and which signal cascade contributes to that in the striatum. Here we show that both neurons and astrocytes of the striatum exhibited, the spontaneous slow Ca²⁺ oscillations, which lasted up to approximately 200 s. This slow Ca²⁺ oscillation was blocked by the depletion of the intracellular Ca²⁺ store and by an antagonist of inositol 1,4,5-trisphosphate (IP₃) receptors. We found that mGluR5 decreased significantly the rate of the slow Ca²⁺ oscillation in both neurons and astrocytes. Thus, the mGluR5-IP₃ signal cascade is the primary contributor to the slow Ca²⁺ oscillation in both neurons and astrocytes. To clarify the cell type of striatal neurons, we conducted the Ca²⁺ imaging study in the transgenic mice expressing yellow fluorescent protein (YFP) in D1 or D2 dopamine receptor (D1R or D2R)-positive neurons. In this study, we found the slow Ca²⁺ oscillations in both the D1R- and D2R-positive neurons in the striatum. This result suggested that striatal projection neurons participating direct and indirect pathway exhibited the slow Ca²⁺ oscillations.