Involvement of Acetylcholine and Na+,K+-ATPase in the Regulation of Skeletal Muscle Growth in a Chicken Embryo

Recently, much attention has been paid to the discussion ofthe trophic function of the nervous system and its involvement intriggering the signaling cascades that regulate cellular metabolism. Therole of acetylcholine and Na+,K+-ATPasein the regulation of skeletal muscle growth was evaluated in 10-12-day-oldchicken embryos under conditions of organotypic tissue culture. Acetylcholinehad a maximum trophotropic effect at a concentration 10(-8) M.An inhibitory analysis proved the involvement of the nicotinic acetylcholinereceptor (nAChR) in this effect. Ouabain regulated the growth ofskeletal muscle explants in a dose-dependent manner. At concentrationscomparable to the physiological, it stimulated the growth of experimentalexplants by 33% compared to the control value. Ouabain was foundto have myotoxic properties in the concentration range of 10(-6)-10(-4) M.Acetylcholine abolished the myotoxic effect of ouabain (10(-6) M)both directly, acting on Na+,K+-ATPase,and via the nAChR.