N- and P/Q-type Ca²⁺ channels are abundant in nerve terminals where they interact with proteins of the release apparatus, including syntaxin 1A and SNAP-25. In previous studies on N- or P/Q-type Ca²⁺ channels, syntaxin 1A co-expression reduced current amplitudes, increased voltage-dependent inactivation and/or enhanced G inhibition. However, these studies were conducted in Ca²⁺ channels that exhibited significant voltage-dependent inactivation. We previously reported that N-type current in bovine chromaffin cells exhibits very little voltage-dependent inactivation and we identified the Ca²⁺ channel subunits involved. This study was undertaken to determine the effect of syntaxin 1A on this weakly-inactivating Ca²⁺ channel. Co-expression of syntaxin 1A with the weakly-inactivating bovine N-type Ca²⁺ channels in Xenopus oocytes did not appear to alter inactivation but dramatically reduced current amplitudes, without changing cell surface expression. To further understand the mechanisms of syntaxin 1A regulation of this weakly-inactivating channel, we examined mutants of the _1b subunit, _2a subunit and syntaxin. We determined that the synprint site of _1B and the C terminal third of syntaxin 1A were necessary for the reduced current amplitude. In addition we show that enhanced G-protein modulation of the Ca²⁺ current by syntaxin 1A cannot explain the large suppression of Ca²⁺ current observed. Most significantly syntaxin increased voltage-dependent inactivation in channels containing mutant _2a subunits that cannot be palmitoylated. Our data suggest that changes in inactivation cannot explain the reduction in current amplitude produced by co-expressing syntaxin and a weakly-inactivating Ca²⁺ channel.