title: Distribution and kinetics of CoEDTA in smooth muscle, and its use as an extracellular marker.
abstract: 1. [(60)Co]EDTA has been evaluated as an extracellular marker in guinea-pig taenia coli and rabbit myometrium.2. The complex was found to be stable, non-toxic, convenient to use and had the advantage of being readily measured without interfering with the analysis of water and electrolyte contents.3. In both smooth muscles [(60)Co]EDTA distributed rapidly into a volume equivalent to that available to [(14)C]sorbitol and slightly greater than that available to inulin.4. The optimum concentrations of carrier required to effectively saturate any adsorption sites were 0.1 mM-CoEDTA for taenia coli and 1.0 mM for myometrium.5. [(60)Co]EDTA was distributed into a volume equivalent to the total water content of rabbit tendon, indicating that it was not excluded from connective tissue water.6. About 5% of the [(60)Co]EDTA taken up by smooth muscle in 15 minutes exhibited slow efflux kinetics. This property was also exhibited by [(14)C]sorbitol and has been reported for other extracellular markers.7. The efflux of 95% of [(60)Co]EDTA followed bulk diffusion kinetics for both taenia coli and myometrium.8. The simultaneous efflux of (24)Na indicated that 1-2% exchanged slowly while 98-99% of the (24)Na exchange could be described by bulk diffusion kinetics, similar to [(60)Co]EDTA. About 15% of this (24)Na was contained outside of the [(60)Co]EDTA space.9. More detailed studies involving the analysis of simultaneous efflux of [(60)Co]EDTA and (24)Na may help to locate and characterize the properties of the excess rapidly exchanging sodium (12-15 m-equiv/kg. wet wt.) in smooth muscle.
mesh_terms: D000818:Animals; D002247:Carbon Isotopes; D003036:Cobalt Isotopes; D004492:Edetic Acid / Q000378:metabolism*; D005110:Extracellular Space; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007420:Intestine, Large; D007444:Inulin / Q000378:metabolism; D007700:Kinetics; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism*; D011817:Rabbits; D012975:Sodium Isotopes; D013012:Sorbitol / Q000378:metabolism; D013710:Tendons / Q000378:metabolism; D014599:Uterus
chemical_list: D002247:Carbon Isotopes; D003036:Cobalt Isotopes; D012975:Sodium Isotopes; D013012:Sorbitol; D007444:Inulin; D004492:Edetic Acid