BHQ, heparin sodium reduces or eliminates EPSPs at crayfish neuromuscular junctions

Abstract

Internal calcium stores have been shown to have an effect on synaptic transmission. Our objective in this experiment was to see how the depletion or inhibition of internal calcium stores would affect synaptic transmission. We added two drugs to our crayfish preparation: Butylhydroquinone, a food preservative, and sodium heparin, a common anticoagulant. We used Butylhydroquinone (BHQ) to inhibit the sarcoplasmic-endoplasmic calcium ATPase (SERCA) pumps on the endoplasmic reticulum (ER) to deplete the internal Calcium stores in the cell. We blocked the IP3 receptors on the ER that are responsible for releasing calcium using sodium heparin. We used BHQ and heparin together to see how their combined effects would affect the EPSPs. Finally, we washed the BHQ and heparin off the crayfish and took EPSP recordings to determine if a calcium rebound occurs. We found that both BHQ and heparin decrease EPSPs. When used together, the drugs decrease the amplitude as well. We were unable to demonstrate a calcium rebound into the ER.