Figure 5.

Inhibition of the voltage-dependent enhancement of neurotransmitter release by synprint peptide in the presence of thapsigargin. (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). Sixty-five micrometers of L_II-III(718–963) was injected at t = 0 in the presence of 2 μM thapsigargin in Krebs solution containing 0 mM Ca²⁺ and 10 mM Mg²⁺. mEPSPs from one representative experiment recorded 5 and 4 min before injection and 10, 11, 25, and 26 min after injection are illustrated. (b) Difference between normalized average integral values of the mEPSPs with and without presynaptic action potentials is plotted from five experiments like the one illustrated in a.