BK channels sustain neuronal Ca2+ oscillations to support hippocampal long-term potentiation and memory formation

• DOI: 10.1007/s00018-023-05016-y
• Publication Date: 2023-11-21T19:04:47Z
• Authors: Thomas Pham; Tamara Hussein; Dila Calis; Helmut Bischof; David Skrabak; Melanie Cruz Santos; Selina Maier; David Spähn; Daniel Kalina; Stefanie Simonsig; Rebekka Ehinger; Bernhard Groschup; Marlies Knipper; Nikolaus Plesnila; Peter Ruth; Robert Lukowski; Lucas Matt
• Keywords: Neurons; Mice, Knockout; 570; 0303 health sciences; Neuronal Plasticity; Long-Term Potentiation; 610; Hippocampus; Mice; 03 medical and health sciences; Animals; Original Article; Large-Conductance Calcium-Activated Potassium Channels

AbstractMutations of large conductance Ca2+- and voltage-activated K+ channels (BK) are associated with cognitive impairment. Here we report that CA1 pyramidal neuron-specific conditional BK knock-out (cKO) mice display normal locomotor and anxiety behavior. They do, however, exhibit impaired memory acquisition and retrieval in the Morris Water Maze (MWM) when compared to littermate controls (CTRL). In line with cognitive impairment in vivo, electrical and chemical long-term potentiation (LTP) in cKO brain slices were impaired in vitro. We further used a genetically encoded fluorescent K+ biosensor and a Ca2+-sensitive probe to observe cultured hippocampal neurons during chemical LTP (cLTP) induction. cLTP massively reduced intracellular K+ concentration ([K+]i) while elevating L-Type Ca2+ channel- and NMDA receptor-dependent Ca2+ oscillation frequencies. Both, [K+]i decrease and Ca2+ oscillation frequency increase were absent after pharmacological BK inhibition or in cells lacking BK. Our data suggest that L-Type- and NMDAR-dependent BK-mediated K+ outflow significantly contributes to hippocampal LTP, as well as learning and memory.