Conductance pathways in fundic gastric mucosa

Academic Article

Abstract

  • Fundic gastric mucosa with multiple cell types presents problems in quantitation of conductance pathways. It is possible to quantitate cellular and paracellular conductance by 2 techniques. Using 2 microelectrodes, one to send 5.9x10-9 amps intracellularly and a second to measure the resulting ΔV in cells at various distances, intracellular coupling is demonstrated and the ΔV conforms to the differential equation (d2V2/dr2) + l/r(dv/dr) - (1/λ2)V=O. The space constant for correct spread is 408 ± 217 μ. From an equivalent circuit the cell and shunt resistances are 2392 and 9092 Ωcm2 respectively. The second technique utilizes a serosal Δ[K+] to cause a ΔEMF across the serosal cell membranes. The change in PD across the serosal membrane of surface cells (Δpsisc) is compared to the transepithelial PD (Δpsims). The data is analyzed according to an equivalent circuit representing 2 cell types, surface (non primed) and oxyntic (primed). E refers to EMFs, R to resistances, m to mucosal membranes, S to serosal membrane and L to the shunt. Rc is the intercellular coupling resistance. Rc is taken to be small and approaches zero. In this circumstance (Δpsisc)/(Δpsims) = l+CRmRm') / R(L) (Rm+Rm'). The shunt resistance is 12,802 Ωcm2 while the cellular resistance is 3138 Ωcm2. Thus the shunt contributes only 20% of tissue conductance.
  • Published In

  • The FASEB Journal  Journal
  • Author List

  • Spenney JG; Shoemaker RL; Sachs G
  • Volume

  • 33
  • Issue

  • 5 II