Ca²⁺ ATP-ase in the Endoplasmic Reticulum has Little Effect on Synaptic Plasticity Following Tetanic Stimulation

Abstract

Since internal calcium levels influence synaptic transmission, changing the amount of calcium uptake by internal organelles such as the endoplasmic reticulum (ER) should change the magnitude of EPSP amplitudes, a measurement of synaptic transmission. We changed the amount of calcium uptake by the ER by adding two different chemicals that had opposite effects on the Ca²⁺ ATP-ase pump in the ER. In the first experiment, we added the drug, Ochratoxin A, which enhanced this pump, causing an increase in calcium uptake. In the second experiment, we added the drug, BHQ, which inhibited this pump, causing a decrease in calcium uptake. We then compared the percent change in amplitude of EPSPs following tetanic stimulation for each chemical. We expected that Ochratoxin A would decrease the percent change in post-tetanic EPSP amplitude, while BHQ would increase the percent change. However, we found that both chemicals caused an increase in percent change in post-tetanic EPSP amplitude, though neither test displayed results that were significantly different from trials without the addition of either chemical (p<0.05).