Long‐term high‐intensity sound stimulation inhibits Ih in CA1 pyramidal neurons.

Abstract

Afferent neurotransmission on hippocampal pyramidal cells can change their intrinsic membrane properties and affect many ion currents. One of the most plastic neuronal currents is the hyperpolarization activated cationic current (Ih), which changes in CA1 pyramidal cells in responseto many types of physiological and pathological processes. Several evidences demonstrated that hippocampal CA1 pyramidal neurons are affected by auditory stimulation. Recently we demonstrated that long‐term potentiation (LTP) is depressed by high‐intensity sound stimulation. Here we investigated if a long‐term high‐intensity sound stimulation could affect intrinsic membrane properties of CA1 pyramidal neurons. Our results showed that Ih is depressed by longterm (2 minutes per day, for 10 days) high intensity sound (110 dB) exposure. This resulted in a decreased resting membrane potential, increased membrane input resistance and time constant, and decreased action potential threshold. In contrast, CA1 pyramidal neurons from sound‐exposed animals fired more action potentials than neurons from control animals, but this effect was not caused by a decreased Ih. Interestingly, a single episode (1 minute) of 110 dB sound stimulation which also inhibits hippocampal LTP did not affect Ih and firing in pyramidal neurons, suggesting that these are long‐term responses to high intensity sound exposure. Our results show that prolonged exposure to high‐intensity sound affects intrinsic membrane properties of hippocampal pyramidal neurons mainly by decreasing the amplitude of Ih.Support or Funding InformationFAPESP, CNPQ and CapesThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.