Intracellular free magnesium concentration in the taenia isolated from guinea-pig caecum
Nakayama, S.; Tomita, T.
Progress in Clinical and Biological Research 327: 345-349
1990
ISSN/ISBN: 0361-7742 PMID: 2320608 Document Number: 359472
The free [Mg]i in the guinea-pig taenia was estimated to be about 300 microM. The [Mg]i remained constant by simple removal of Ca, but reduced by removal of both Ca and Mg, reaching about 8 microM in 100 min. This recovered on Mg readmission. No clear recovery was observed in Na-free (K-substitute) solution containing 2.4mM Ca. Carbachol response was reversibly inhibited when [Mg]i decreased to less than 1/10 of the control. In K-free solution [Mg]i gradually increased to more than 500 microM in 100 min in the absence of Ca, but not in the presence of Ca. A Na-Mg exchange process seems to be playing an important role, in addition to a low permeability of the membrane to Mg, in the regulation of [Mg]i.