Salts of short-chain fatty acids increase the activity of the large conductance, Ca²⁺-activated K⁺ channels and reduce calcium oscillations in rat GH3 cells

The short-chain fatty acids such as acetic, propionic and butyric acids are microbiota metabolites that can exert a series of physiological effects both in the intestine and other organs, including the central nervous system. The present work aimed to examine the effects of sodium acetate, propionate, and butyrate on the activity of large conductance Ca²⁺ activated K⁺ channels and calcium oscillations in rat pituitary GH3 cells. It has been shown that fatty acids under study cause a dose-dependent increase in the amplitude of total outward potassium currents and these effects are prevented by tetraethylammonium, a Ca²⁺ activated K⁺ channel blocker, indicating the involvement of Ca²⁺ activated K⁺ channels in the effects of fatty acids. It is worthy of note that fatty acids increased open probability of single channels with no changes in the amplitude and the mean channel open time. In addition, fatty acids were associated with a significant reduction in the amplitude and frequency of Ca²⁺ oscillations in GH3 cells. An increase in potassium conductance and a decrease in the intracellular Ca²⁺ level can mediate the effects of short-chain fatty acids in various excitable structures, such as a relaxation of intestinal and vascular smooth muscle cells, hyperpolarization of neurons, and the regulation of hormone and neurotransmitter release.