Fig. 2.

Examples of ratemeter records from extracellular recordings of Purkinje neurons from an aged rat maintained for 8 months (from 6–15 months of age) on a control (A–C) or strawberry (D–F) diet. In Aand D, the baseline response to GABA is shown. The dose of GABA was adjusted to produce a 15–30% inhibition of the Purkinje cell firing rate. In B and E, isoproterenol was coapplied with GABA. In the control, aged rat, isoproterenol had no effect at lower doses (data not shown) and, at a high dose the GABA inhibition was reduced, and the baseline firing rate was diminished. In contrast, in the aged rat that was maintained on the strawberry diet, isoproterenol increased the GABA inhibition to 98%. This is similar to what has been previously observed in young rats.C and F show recovery back to preisoproterenol levels of GABA inhibition. Bars above the ratemeter indicate the drug application times. Thehorizontal calibration bar indicates time in seconds, whereas the vertical calibration bar indicates the firing rate of the Purkinje neuron in action potentials per second.