The starting concentration of the radioisotope in the hemolymph half chamber (DPM ⋅ l–1) was divided by the concentration of Ca2+ (10 mM) in the Ringer solution to give the specific activity in DPM ⋅ (mmol Ca2+)–1.
The amount of DPM from the 45Ca accumulated in the shell half chamber at each time point was multiplied by 80 to achieve the total DPM in the 4 ml volume. The total amount of Ca2+ (mM) transferred across the OME was then calculated from the total DPM using the specific activity according to Eq. 2.
The slope of the Ca2+ accumulation across 90 min was determined and the transport rate was expressed as nM ⋅ min–1.
The permeability of the paracellular pathways was described by the apparent permeability (Papp) of 3H-mannitol across the OME, which was calculated using Eq. 3
in which dQ ⋅ dt–1 describes the appearance of 3H-mannitol on the shell side (mol ⋅ s–1), Ac the surface area of the chamber opening (0.75 cm2) and C0 the initial concentration of 3H-mannitol on the hemolymph side (mol ⋅ ml–1).
The amount of DPM from the 45Ca accumulated in the shell half chamber at each time point was multiplied by 80 to achieve the total DPM in the 4 ml volume. The total amount of Ca2+ (mM) transferred across the OME was then calculated from the total DPM using the specific activity according to Eq. 2.
The slope of the Ca2+ accumulation across 90 min was determined and the transport rate was expressed as nM ⋅ min–1.
The permeability of the paracellular pathways was described by the apparent permeability (Papp) of 3H-mannitol across the OME, which was calculated using Eq. 3
in which dQ ⋅ dt–1 describes the appearance of 3H-mannitol on the shell side (mol ⋅ s–1), Ac the surface area of the chamber opening (0.75 cm2) and C0 the initial concentration of 3H-mannitol on the hemolymph side (mol ⋅ ml–1).
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