Figure 6. Activity-dependent rises in lactate are triggered by postsynaptic currents and blocked by AMPA receptor antagonists.

Effect of topical application of CNQX on climbing fibre stimulation-evoked rises in extracellular lactate and LFP response amplitudes. A, top panel illustrates the times of superfusion with CSF, CSF + drug and wash-out of drug with CSF. The green forest of peaks below this correspond to the raw lactate levels, the red dotted lines indicate the start and end of stimulation. Below this are individual traces of LFPs; a typical example has been chosen for the designated time period. The figure shows that under control conditions (CSF) climbing fibre stimulation induced LFP responses and increases in extracellular lactate, while CNQX, a specific blocker of AMPA receptors, abolished both responses. Following a prolonged wash-out period, both LFP and lactate responses returned to control levels. B, histogram summarizing effect of CNQX on lactate response. The figure shows the averaged responses (n = 10 in 6 animals); values are mean ±s.e.m. displayed as a difference from zero. CNQX readings are taken from stimulations after 35 min of drug application. Wash-out readings were taken when the LFP response amplitudes began to gain amplitude. P values are calculated as a result of paired Student's t tests between individual values of the same animal.