TY - JOUR AU - Schatzkin, Eric AU - Watsa, Nayantara PY - 2004 TI - The CA 2+ /ATPase Pump in the Endoplasmic Reticulum Affects EPSP Amplitudes and Synaptic Facilitation at the Crayfish Neuromuscular Junction JF - Pioneering Neuroscience; Vol 5 (2004) KW - N2 - There are four mechanisms that remove Ca 2+ from the presynaptic nerve terminal following an action potential. They are: the Na 2+ /Ca 2+ exchanger, the Ca 2+ /ATPase pump in the mitochondria, the Ca2+/ATPase pump in the plasma membrane, and the Ca 2+ /ATPase pump in the endoplasmic reticulum (E.R.). The objective of this experiment was to investigate the importance of the Ca 2+ /ATPase pump in the E.R. in removing Ca 2+ from the cell. We tested the relative importance of this pump by measuring excitatory post synaptic potential (EPSP) amplitudes and synaptic facilitation. To do this, we compared normal twin pulse facilitation to twin pulse facilitation in crayfish under the effects of Ochratoxin A, a drug that enhances the functioning of the Ca 2+ /ATPase pump and twin pulse facilitation in the presence of BHQ, a drug that inhibits the functioning of the Ca 2+ /ATPase pump. We found that Ochratoxin A has a depressive effect on both EPSP amplitude and synaptic facilitation, while BHQ had the opposite effect. Our results indicate that the Ca 2+ /ATPase pump in the E.R. plays a significant role in regulating the amount of residual Ca 2+ in the presynaptic nerve terminal. UR - https://ojs.grinnell.edu/index.php/pnsj/article/view/146