Table 1.

Effects of the Mid peptide on evoked EPSPs

Injected reagent	Frequency of stimulation, Hz	Ca2+ concentration, mM	No. of experiments	Change in amplitude, %
Mid peptide	0.01	5.1	5	−14  ± 19*
Mid peptide	0.05	5.1	7	−29  ± 1.8†
Mid peptide	0.2	5.1	5	−32  ± 3.8‡
Mid peptide	0.05	1	5	−51  ± 7.1§
Mid peptide	0.2	1	5	−59  ± 5.5¶
Control m-Mid peptide	0.05	5.1	6	−6  ± 11‖
Control s-Mid peptide	0.05	5.1	6	−10  ± 6.8‖
Carrier solution	0.05	5.1	7	−3  ± 2.4‖
Carrier solution	0.2	5.1	5	−8  ± 2.3‖

Samples to be tested were introduced into presynaptic neurons. Concentrations of the Mid peptide and the control peptides in the pipette were 2.5 mM. EPSPs were evoked by presynaptic action potentials elicited at the indicated frequencies of stimulation. Neurons were superfused with modified Krebs solution containing the indicated concentrations of Ca²⁺. EPSPs were measured when maximum inhibitory effect was observed at 60*, 40–50, 

^† 25–30, 

^‡ 30–50, 

^§ and 40–60 

^¶ min after starting injection. 

^‖EPSPs were measured at 30 min after the injection of the control peptides or the carrier solution. Changes in amplitude of EPSPs were expressed as percent inhibition of the preinjection value (mean ± SEM).