Influence of potassium p-aminobenzene thiosulfate on the membrane potential and ATPase activity of the plasmatic membrane of the embryos of weatherfish (Misgurnus fossіlis)

Abstract

We studied the effects of the newly synthesized biologically active compound potassium aminobenzene thiosulfonate on electrophysiological parameters of the embryos of weatherfish (Misgurnus fossіlis L.), in particular the dynamics of transmembrane potential (TMP) of the plasmatic membranes of the weatherfish and the activity of the membrane enzyme Na+/K+–ATPase during synchronous cleavage of blastomeres in early embryogenesis. A slight impairment of electrogenesis of the cellular membranes under the action of potassium aminobenzene thiosulfonate indicates changes in the permeability of plasmatic membrane and transport of electrogenic ions. This was related to the inhibition of biosynthetic processes in the first hours of the development of embryos, which led to 60.6 ± 2.6% decrease in the activity of membrane pump when subject to high (10–3 М) concentration of potassium aminobenzene thiosulfonate. Its activity further recovered to the level of the control only in 10–8 М concentration. Also, we conducted a comparative analysis of the effects potassium aminobenzenethiosulfonate had on the activity of the membrane pump of embryos in in vivo and in vitro experiments. We determined that the action of the examined compound depends on the presence of a correspondding concentration in the embryo incubation medium. To characterize the variability of changes in the activity of membrane pump of the embryos in the conditions of action of potassium aminobenzene thiosulfonate, we determined constants of semi-inhibition (І50) by linearization of the developed concentration-effect curves using Hill’s plot. To determine which factors contribute to the changes in the activity of membrane pump the most, namely, various concentrations of potassium p-aminobenzene thiosulfonate, duration of the development of embryos or other factors that had not been taken into account, we performed a dispersion analysis of how these factors affect the variability of the studied parameter. We determined that the extent of variability of the activity of the membrane pump is also determined by the effect of different concentrations of potassium p-aminobenzene thiosulfonate, and the factor of time of embryo development. The electronic-microscopic study of weatherfish’s blastomeres subject to potassium p-aminobenzene thiosulfonate revealed the changes in the ultrastructure of mitochondria, which led to inhibition of their matrix and electron transport chain, and therefore decrease the efficiency of ATP production and energy-dependent processes.

Keywords

• potassium p-aminobenzene thiosulfonate; transmembrane potential; weatherfish embryos; ultrastructure.