Figure 2.

Effects of the N-type Ca²⁺ channel synprint peptide on voltage-dependent enhancement of transmitter release. (a) mEPSPs induced by 0.5 M sucrose (Left) or 0.5 M sucrose plus a presynaptic tetanic stimulation at 100 Hz for 4 s (Right) are shown. L_II-III(718–963) of α_1B was introduced into the presynaptic cell bodies at t = 0 from a pipette containing 65 μM peptide in Krebs solution containing 0 mM Ca²⁺ and 10 mM Mg²⁺. mEPSPs from one representative experiment recorded 5 and 4 min before injection and 15, 16, 25, and 26 min after injection are illustrated. (b) Normalized average mEPSP integral values with and without presynaptic action potentials, 400 pulses at 100 Hz, are plotted from nine experiments like the one illustrated in a. Dotted line shows the mEPSP integral values from control experiments shown in Fig. 3b.