Sulforhodamine 101 is a red emitting fluorophore with an extinction coefficient of 105000. Sulforhodamine 101 is ideally used to label astrocytes in the rodent neocortex which can be observed with two-photon microscopy. In addition, Sulforhodamine 101 is used to determine morphological characteristics of astrocytes and to observe the association of astrocytes with the cortical microvasculature. Furthermore, this fluorophore is used as an activity-dependent dye for monitoring regulated exocytosis. Alternate studies suggest that Sulforhodamine 101 can increase intrinsic neuronal excitability and long-lasting increases in evoked EPSCs in CA1 pyramidal neurons in hippocampal slices. Sulforhodamine 101 enhances evoked synaptic N-methyl D-aspartate receptor (NMDAR) currents which can be blocked by the antagonist, AP-5. Sulforhodamine 101 is a red emitting fluorophore with an extinction coefficient of 105000. Sulforhodamine 101 is ideally used to label astrocytes in the rodent neocortex which can be observed with two-photon microscopy. In addition, Sulforhodamine 101 is used to determine morphological characteristics of astrocytes and to observe the association of astrocytes with the cortical microvasculature. Furthermore, this fluorophore is used as an activity-dependent dye for monitoring regulated exocytosis. Alternate studies suggest that Sulforhodamine 101 can increase intrinsic neuronal excitability and long-lasting increases in evoked EPSCs in CA1 pyramidal neurons in hippocampal slices. Sulforhodamine 101 enhances evoked synaptic N-methyl D-aspartate receptor (NMDAR) currents which can be blocked by the antagonist, AP-5. A red-emitting flurophore used to label astrocytes.