Induction of αCaMKII Expression by KCl in Cultured Primary Cerebellar Granule Neurons

Background: The cerebellum specializes in functions, such as motor learning. One of the abundant types of neuronal cells present in the cerebellum is the cerebellar granule (CG) cell. While CG cells exhibit synaptic plasticity, it has been found that CaMKinase II alpha (αCaMKII), an enzyme important in multiple forms of plasticity in other regions of the brain, is not expressed in CG cells in vivo, as observed by immunohistochemical analysis of the rat cerebellum. However, we observed that αCaMKII is expressed in primary cultures of rat CG cells, although the expression profile of several other proteins involved in calcium-based signaling mimics their expression pattern in vivo. KCl in culture is known to induce membrane depolarization in a concentration-dependent manner, which is also influenced by the age of the culture in vitro. Objectives: We assessed the factors responsible for the expression of αCaMKII in primary CG cells. Materials & Methods: The presence of αCaMKII in primary CG cells in vitro was analyzed by both mRNA transcript and protein analysis. To study the effect of different concentrations of KCl on primary CG cells, Western blot analysis and immunocytochemistry were employed. Results: The results show that αCaMKII in primary CG cells in vitro is induced by KCl, which is supplemented in the medium to promote the survival of the cells. Conclusion: The study reports for the first time that αCaMKII, which is absent in CG cells in vivo, is induced by KCl used to grow the primary CG cells in vitro. The expression increases with enhanced concentrations of KCl.