(a) Left, example traces of the currents induced by photolysis of dcPNPP-Glu in control and following treatment with the mGluR1/5 antagonists JNJ16259685 (1 μM) and MPEP (3 μM). Right, example traces of currents induced by photolysis of DEAC454-GABA in control and following treatment with the GABA-B receptor antagonist CGP-55845a (500 nM). Note, the fast ionotropic inward current was unaffected in both cases. (b) Left, summary of currents induced by photolysis of dcPNPP-Glu by near-UV and blue light. Solid black line indicates the mean current and the gray area indicates the standard error of the mean. Right, summary of the increase in outward current induced by longer duration flashes (n = 8 cells). Blue light applied for longer than 100 ms resulted in an inward current that was also blocked by mGluR antagonists (not shown). (c) Left, summary of outward current induced by photolysis of DEAC454-GABA by blue and near-UV light. Solid black line indicates the mean current and the gray area indicates the standard error of the mean. Right, summary of the increase in current induced by longer pulses of light (n = 8 cells). Recordings were made in the presence of NMDA (CPP, 10 μM) and D2 receptor (sulpiride, 2 μM) antagonists. Those in (b/c) also contained GABA-A (picrotoxin, 10 μM) and AMPA receptor (CNQX, 10 μM) antagonists. For all cells, a single data point was collected at each flash duration and the data were averaged across cells.