A battery of genetically encoded calcium indicators (GECIs) with different binding kinetics and calcium affinities was developed over the recent years to permit long-term calcium imaging. GECIs are calcium buffers and therefore, expression of GECIs may interfere with calcium homeostasis and signaling pathways important for neuronal differentiation and survival. Our objective was to investigate if the biolistically induced expression of five commonly used GECIs at two postnatal time points (days 14 and 22–25) could affect the morphological maturation of cortical neurons in organotypic slice cultures of rat visual cortex. Expression of GCaMP3 in both time windows, and of GCaMP5G and TN-XXL in the later time window impaired apical and /or basal dendrite growth of pyramidal neurons. With time, the proportion of GECI transfectants with nuclear filling increased, but an only prolonged expression of TN-XXL caused higher levels of neurodegeneration. In multipolar interneurons, only GCaMP3 evoked a transient growth delay during the early time window. GCaMP6m and GCaMP6m-X_C were quite “neuron-friendly.” Since growth-impaired neurons might not have the physiological responses typical of age-matched wildtype neurons the results obtained after prolonged developmental expression of certain GECIs might need to be interpreted with caution.

近年来，开发了一系列具有不同结合动力学和钙亲和力的遗传编码钙指示剂（GECI），以实现长期钙成像。GECIs是钙缓冲剂，因此，GECIs的表达可能会干扰钙稳态和对神经元分化和存活至关重要的信号通路。我们的目的是研究在两个出生后的时间点（第14天和第22-25天）通过生物弹射诱导的5种常用GECI的表达是否会影响大鼠视皮层器官型切片培养中皮质神经元的形态成熟。在两个时间窗口中GCaMP3的表达，以及在随后的时间窗口中GCaMP5G和TN-XXL的表达损害了锥体神经元的根尖和/或基底树突生长。随着时间的推移，带有核填充的GECI转染子的比例有所增加，但TN-XXL的仅延长表达导致较高水平的神经变性。在多极中间神经元中，只有GCaMP3在早期时间窗口内引起了短暂的生长延迟。GCaMP6m和GCaMP6m-X_C相当“对神经元友好”。由于生长受损的神经元可能没有年龄匹配的野生型神经元所具有的典型生理反应，因此某些GECIs长时间表达后获得的结果可能需要谨慎解释。