Modulation of calcium signalling by the endoplasmic reticulum in Carassius neurons

•We firstly show that the ER participates in Ca2+ signalling of Carassius neurons.•SERCA pump is activated immediately after the beginning of Ca2+ entry the cell.•The ER does not influence basal level of intracellular Ca2+ in Carassius neurons.•The ER modulates the shape of Ca2+ signals in cerebellar neurons.•The ER plays significant role in the short-term modulation of Ca2+ signals. It is known that endoplasmic reticulum (ER), being a calcium store participates in the regulation of intracellular calcium concentration. Ca-ATPase of the ER is one of the crucial agents providing the calcium-accumulating function of this intracellular structure. We studied the role of the ER in modulation of calcium signalling in Carassius neurons using a Ca2+-imaging technique. We tested the role of the ER in the maintenance of a steady state calcium level in the cytoplasm and in modulation of Ca2+ transients evoked by cell depolarizations. The ER calcium stores were depleted using inhibitors of ER Ca-ATPase, which provided blocking of Ca2+ uptake by the ER. Our experiments firstly showed that the ER can significantly modulate the characteristics of intracellular calcium signals in Carassius neurons during their activity. These findings also indicate that the ER modulates the shape of Ca2+ signals rather than the basal level of intracellular Ca2+ in these neurons.