ISSN:
1432-2013
Keywords:
Frog spinal cord
;
Motoneurones
;
Glia cells
;
Ion sensitive microelectrodes
;
Extra- and intracellular activities of K+, Na+ and Cl−
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Intra- and extracellular ion activities were measured with ion sensitive microelectrodes in motoneurones and glia cells of the spinal cord of the frog. These data were corrected for cross sensitivities of the ion exchangers to intracellular interfering ions, and equilibrium potentials for K+, Na+, Ca2+ and Cl− (E K,E Na,E Ca andE Cl) were calculated. In motoneurones with membrane potentials exceeding −60mV the following mean equilibrium potentials were determined. $$\begin{gathered} E_{Na} = + 29.4mV, E_K = - 87.9mV, E_{Ca} = + 52.6mV, \hfill \\ E_{Cl} = - 34.1mV \hfill \\ \end{gathered}$$ . The corresponding values for glia cells were: $$\begin{gathered} E_{Na} = + 40.5mV, E_K = - 84.0mV, E_{Ca} = + 35.7mV, \hfill \\ E_{Cl} = - 59.7mV \hfill \\\end{gathered}$$ . The intracellular ionic milieu is probably disturbed by the impalement of the cells. This transiently decreases the intracellular K+ and increases intracellular Na+. These effects were estimated and their origin is discussed. The results of the experiments suggest a non-passive transmembrane distribution of K+, Na+ and Ca2+ in motoneurones and glia cells, a non-passive transmembrane distribution of Cl− in motoneurones, and a passive transmembrane distribution of Cl− in glia cells.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00615519
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