Figure 6.

NPY does not alter presynaptic glutamate release. A, A bipolar stimulating electrode was placed in L2/3 and used to elicit EPSPs with a paired-pulse stimulus (10 ms interstimulus interval) with the stimulus strength set to elicit responses of low (25%), medium (50%), and high (75%) amplitudes, relative to maximal EPSP responses. B, EPSP amplitude of the first pulse (P1), second pulse (P2), and paired-pulse ratio (P2/P1) was not affected by NPY (1 μm) nor Y1 antagonist BIBO 3304 (1 μm) application for low (p = 0.7523; n = 5), medium (p = 0.6592; n = 4), or high (p = 0.1997; n = 5) levels of stimulation (one-way ANOVA with Dunnett's multiple comparison test). C, Single EPSP trace before and after train of 100 EPSPs at 1 Hz (black line). After NPY (1 μm) application, the rundown protocol was repeated. The 100th EPSP after NPY application is shown in gray. D, NPY (1 μm) did not change the average EPSP amplitude for the 1st or 100th EPSP (n = 4; p = 0.8397, one-way ANOVA). Error bars indicate ±SEM.