L-Type Calcium Channel Modulates Low-Intensity Pulsed Ultrasound-Induced Excitation in Cultured Hippocampal Neurons
Wen‑Yong Fan1,2 · Yi‑Ming Chen3,4 · Yi‑Fan Wang3,4 · Yu‑Qi Wang1,2 · Jia‑Qi Hu1,2,5 · Wen‑Xu Tang1,2 · Yi Feng6 · Qian Cheng3,4,7 · Lei Xue1,2,81 State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200433, China
2 Department of Physiology and Neurobiology, School of Life Sciences, Fudan University, Shanghai 200438, China
3 Institute of Acoustics, School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
4 Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji University, Shanghai 200070, China
5 Center for Rehabilitation Medicine, Department of Pain Management, Zhejiang Provincial People’s Hospital, Afliated People’s Hospital, Hangzhou Medical College, Hangzhou 310014, China
6 Department of Critical Care Medicine, Shanghai General Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200080, China
7 Shanghai Research Institute for Intelligent Autonomous Systems, Tongji University, Shanghai 201210, China
8 Research Institute of Intelligent Complex Systems, Fudan University, Shanghai 200433, China
Abstract
As a noninvasive technique, ultrasound stimulation is known to modulate neuronal activity both in vitro and in vivo. The latest explanation of this phenomenon is that the acoustic wave can activate the ion channels and further impact the electrophysiological properties of targeted neurons. However, the underlying mechanism of low-intensity pulsed ultrasound (LIPUS)-induced neuro-modulation effects is still unclear. Here, we characterize the excitatory effects of LIPUS on spontaneous activity and the intracellular Ca2+ homeostasis in cultured hippocampal neurons. By whole-cell patch clamp recording, we found that 15 min of 1-MHz LIPUS boosts the frequency of both spontaneous action potentials and spontaneous excitatory synaptic currents (sEPSCs) and also increases the amplitude of sEPSCs in hippocampal neurons. This phenomenon lasts for > 10 min after LIPUS exposure. Together with Ca2+ imaging, we clarified that LIPUS increases the [Ca2+]cyto level by facilitating L-type Ca2+ channels (LTCCs). In addition, due to the [Ca2+]cyto elevation by LIPUS exposure, the Ca2+-dependent CaMKII-CREB pathway can be activated within 30 min to further regulate the gene transcription and protein expression. Our work suggests that LIPUS regulates neuronal activity in a Ca2+-dependent manner via LTCCs. This may also explain the multi-activation effects of LIPUS beyond neurons. LIPUS stimulation potentiates spontaneous neuronal activity by increasing Ca2+ influx.
Keywords
Low-intensity pulsed ultrasound; Neuromodulation; L-type calcium channel; Hippocampal neuron
