Characteristics of different types of transmitter release
| Subject to Presynaptic Modulation | [Ca2+]o-Dependent | Mode of Release | Ca2+ Channel Involved | TTX-Sensitive | Carrier Involved | |
|---|---|---|---|---|---|---|
| Neuronal frequency-coded | Yes | Yes | Vesicular exocytosis | Yes | Yes | No |
| Ligand-gated | Yes | Yes | Vesicular exocytosis | Yes | Yes | No |
| Carrier-mediated | No | No | Cytoplasmic | No | Yes/no | Yes |
| [K+]oexcess | Yes/no1-a | Yes | Vesicular exocytosis | Yes | No | No |
↵1-a At high [K+]o (extracellular K+ concentration) (>60 mM), there is no presynaptic modulation.