Development of excitability in embryonic chick skeletal muscle cells

Abstract

During embryonic and early postnatal development, the chick leg muscle cells undergo a series of changes in their electrical responses in the following sequence: passive response, plateau response, plateau plus spike response and spike response. This suggests that the electrogenetic mechanism of muscles matures during development; a mechanism producing the plateau may first be induced, and then that producing the spike. The plateau is sensitive to manganese or cobalt ions, while the spike to tetrodotoxin. This suggests that the plateau is related to the increase in permeability to calcium ions, while the spike to sodium ions.

Development of electrophysiological and biochemical membrane properties during differentiation of embryonic skeletal muscle in culture.

“…A prolonged AP outlasting the stimulating pulse by several seconds has been described in embryonic chick myotubes in culture (18,24) and in situ (17). During development in situ this response appears before the fast AP and disappears after hatching (17 (25).…”

“…The expression of these properties is autonomously regulated with no requirement for neuronal intervention. Although a rise in RP during differentiation of myotubes has been reported in culture (13)(14)(15) and in situ (16,17), low synchrony in differentiation produced large variability in electrical responses (17,18) and has hampered determination of the time of appearance and sequence of development of membrane excitability. Fischbach et al (13) The development of contractile activity is indicated by the early appearance of local twitches, which spread through the entire myotube upon maturation.…”

“…During development in situ this response appears before the fast AP and disappears after hatching (17 (25). Concomitant increases in other specialized membrane constituents such as adenylate cyclase (26) and Na+,K+-ATPase (25) also occur during this period, and it is likely that all these rapid and simultaneous changes in membrane properties are coordinately regulated.…”

From Nutrition to Health: The Role of Natural Products – A Review

“…They exist not only in fully differentiated cells but also already in oocytes (Okamoto et al, 1977) and in developing nerve and muscle cells (Spitzer, 1979). There are several reports that calcium channels are restricted to, or more prominent in, the less differentiated states of excitable cells such as skeletal cells (Kano, 1975;Kidokoro, 1973;Kidokoro, 1975) and nerve cells (Matsuda et al, 1978;Mori-Okamoto et al, 1983;Spitzer and Baccaglini, 1976). …”

“…(Fukuda et al, 1976;Kano, 1975;Kano and Yamamoto, 1977). The involvement of a chloride component has also been shown in addition to the sodium and calcium component of the action potential, in particular in the long-lasting plateau phase of the action potential in these muscle cells (Fukuda et al, 1976).The availability of ATP in mammalian neurones is due to its wellknown role as a major energy carrier for cellular metabolism and has been reported to act as a fast transmitter in mammalian brain (Edwards and Gibb, 1993).…”