Fig. 7.

Presynaptic muscimol effect on EPSC amplitudes in lamina III/IV neurons, recorded with a paired pulse protocol. a Example of the inhibitory effect of 2 μM muscimol on 10 individual traces, recorded from an unidentified lamina III/IV neuron: both eEPSC peaks were reversibly depressed. b Mean peak amplitudes of the two peaks are shown from the same neuron as in a. The second/first peak ratio (PPR) was enhanced. c Muscimol caused a significant depression of the first eEPSC amplitude and a significant increase of PPR in a population of seven unlabeled neurons (paired t test: p = 0.013 and p = 0.004, respectively, n = 7). d Effect of muscimol on seven individual eEPSCs recorded from an NK1 receptor positive, lamina III/IV neuron (in the inset: fluorescence image of the neuron, scale bar 20 μm). e Muscimol application reversibly depressed the first eEPSC amplitude and increased PPR in this neuron. f In a sample of seven NK1+ neurons, muscimol significantly depressed the first eEPSC and enhanced PPR (paired t test, p = 0.02 and p = 0.007, respectively, n = 7). g Percentage change of PPR induced by muscimol in the two groups of neurons was not significantly different. h Mean PPR increase obtained at different muscimol concentrations. The number of lamina III/IV neurons tested at each concentration is reported above each bar