Sodium, Potassium, and Magnesium in the Blood of the Snail, Helix pomatia L.

Abstract

Sodium varies from 46 to 129 mM/Kg of water in the blood of fasted Helix pomatia. In fed snails, the concentration is usually below 75 mM/Kg. Magnesium generally varies between 16 and 25 mM/Kg when sodium exceeds 75 mM/Kg, but otherwise between 9 and 15 mM/Kg. Concentrations of potassium, which vary from 2.8 to 10.5 mM/Kg, show a bimodal frequency distribution; in fasted snails, the upper mode predominates at concentrations of sodium above 75.5 mM/Kg while the lower mode is seen at lower concentrations of sodium. If fed snails both modes seem to be present. Potassium and magnesium tend to vary together, but feeding increases the relative concentration of potassium.