Synthesis and characterization of a cyclooctapeptide analogue of ω-agatoxin IVB enhancing the activity of CaV2.1 calcium channels activity in cultured hippocampal neurons

► A cyclopeptidic analogue, so-called EP14, mimicking the loop 2 of ω-agatoxin IVB was synthetized. ► EP14 enhanced voltage dependent Ca2+ currents in cultured hippocampal neurons in a ω-agatoxin IVB-dependent manner. ► EP14 increased depolarization-evoked [Ca2+]i rises in a ω-agatoxin IVB-dependent manner. ► Spontaneous excitatory synaptic transmission was stimulated in the presence of EP14. ► EP14 did not affect cell survival as observed with the MTT assay.