PARTICIPATION OF CA2+-ATPASE IN CALCIUM HOMEOSTASIS OF CEREBELLAR NEURONS IN CRUCIAN

In our experiments the participation ofendoplasmic reticulum Ca2+ -ATPase (SERCA) was studied as a separate intracellular participant of calcium homeostasis in neurons of cerebellum from hypoxia-tolerant fish species--crucian Carassius gibelio. The SERCA's blockers cyclopiazonic acid and tapsigargin were used. Intracellular Ca2+ concentration ([Ca2+]i) was measured by Ca2+ -sensitive dye Fura-2AM and microfluorescent method for measuring free Ca2+ concentration. We established that cerebellar neurons ofcrucian have a well expressed system to clean the cytoplasm from Ca2+ overflow that is presented by SERCA-pump ofendoplasmic reticulum. The switching off a SERCA-pump by means of its selective blockers results in increase of the Ca2+ -transient amplitude and Ca2+ entrance in the cell approximately by 20%-100% in comparison to control depending on duration of depolarization. It is assumed, that SERCA-pump ofcrucian neurons like in mammals substantially affects temporary and amplitude characteristics of calcium signals in neurons and plays a considerable role in cleaning of cytoplasm from Ca2+ during functional activity of the cell.