TY  - JOUR
AU  - Cluphf, Phillip
AU  - Pedersen, Kate
AU  - Vincenti, Jared
PY  - 2003
TI  -  Frequency and duration of action potentials are increased due to extracellular calcium replacement in the crayfish nerve 3
JF  - Pioneering Neuroscience; Vol 5 (2004)
KW  - 
N2  -  Short-term synaptic plasticity is thought to be dependent upon residual calcium ions accumulating in the presynaptic cell after an action potential (AP) has been transmitted at the chemical synapse. We supposed that substitution of manganese, another divalent cation, in extracellular crayfish saline would cause the frequency of the spontaneous APs to decrease and the duration of the APs to increase. Our results indicate that the duration of APs was increased due to extracellular replacement of calcium with magnesium and, contrary to what we originally postulated, we also obtained data showing that the frequency of APs increased as well. We believe this latter result may have been because the calcium charge shielding effect was lost at the synapse, thereby decreasing AP threshold. 
UR  - https://ojs.grinnell.edu/index.php/pnsj/article/view/144