2023, Vol. 27 ›› Issue (26): 4200-4207

Effects of transcranial magneto-acousto-electrical stimulation on voltage-gated sodium and potassium channels in aged mice

Zhang Shuai1, 2, Wang Yixiao1, 2, Wu Jiankang1, 2, Mi Jinrui1, 2, Li Zichun1, 2, Xu Guizhi1, 2   

Abstract: BACKGROUND: Transcranial magneto-acousto-electrical stimulation (TMAES) is a new non-invasive neuromodulation technique, which uses the induced field generated by the coupling of ultrasound and static magnetic fields to regulate the firing activity of the nervous system, but the mechanism of its neuromodulatory effect is not yet clear.
OBJECTIVE: To explore the intrinsic mediating mechanism of TMAES regulating the changes of neural excitability in aged mice.
METHODS: Twenty aged mice were equally and randomly divided into aged control group (receiving pseudo-stimulation), magnetic field group (receiving 0.3 T static magnetic field stimulation), ultrasound group (receiving 2.6 W/cm2 ultrasound stimulation), and magneto-acoustical group (receiving 0.3 T and 2.6 W/cm2 coupling stimulation), with five mice in each group. Simulation in each group was done 2 minutes per day for 14 continuous days. Another five young mice (2 months of age) served as the young group (receiving pseudo-stimulation). Then, patch-clamp technique was used to record the ionic currents of relevant channels during cell activation, inactivation, and reactivation in brain slices of mice.
RESULTS AND CONCLUSION: Compared with the aged control group, TMAES significantly increased the current peak value of sodium channels (P < 0.05), shifted the activation curve of voltage-gated sodium channel currents to the left, shifted the inactivation curve to the right, and shortened the reactivation time (P < 0.05). However, there was a significant difference between magneto-acoustical and young groups (P < 0.05). Compared with the aged control group, TMAES suppressed the current peaks of potassium channels, shifted the activation curves of both transient outward potassium currents and delayed rectifier potassium currents to the right, shifted the inactivation curves of transient outward potassium currents to the left, and extended the reactivation time of transient outward potassium currents. However, there was still a significant difference between magneto-acoustical and young groups (P < 0.05). All these findings indicate that TMAES can activate sodium currents and inhibit potassium currents through altering the dynamic characteristics of relevant ion channels, thereby improving the neural excitability of aged mice, but not up to the level of young mice. This neuromodulation technique is expected to provide potential possibilities for delaying aging.

Key words: transcranial magneto-acousto-electrical stimulation, aged mice, neural excitability, voltage-gated sodium channel, voltage-gated potassium channel