FIG. 1.

Examples of Ca²⁺ transients measured from SCN cells in a brain slice loaded with the Ca²⁺ indicator dye fura2. Each line represents data collected from an individual cell. All of this data was collected in the absence of Mg²⁺ but in the presence of TTX and methoxyverapamil that were included to block voltage-sensitive Na⁺ and Ca²⁺ currents. Top: SCN cells show an increase in Ca²⁺ in response to bath application of NMDA (50 μM, 40 s). Bottom: NMDA-induced Ca²⁺ transients were inhibited by the presence of the NMDA receptor antagonist AP5 (50 μM). Data collected during the night from single SCN slice from a 14-day-old rat.