Chloride/bicarbonate exchanger in rat thymic lymphocytes: experimental investigation and mathematical modeling

Aim: Aim of this research was to investigate the functioning of chloride/bicarbonate exchanger in thymic lymphocytes in view of better understanding the mechanisms involved in chloride fluxes. Materials and methods: Experiments were performed using a suspension of freshly isolated thymocytes representing a homogeneous population of thymic lymphocytes. Thymic lymphocytes were isolated from Wistar male rats' gl. thymus, 6 - 7 weeks of age. The cells were incubated with the MQAE chloride dye. Cl- concentration in the cytoplasm of lymphocytes was measured spectrophotometrically. A model of exchanger activation has been suggested based on the analysis of experimental data. Results and conclusion: It has been shown that: (a) involvement and activity of chloride transport mechanisms depend on where chloride concentration is made zero: in the medium or cytoplasm; (b) under certain experimental conditions, the activity of the exchanger proceeds in two steps: switching on and off; (c) in the absence of HCO3-, the relative rates of the exchanger transitions decline considerably, its efficacy remaining the same. Chloride/bicarbonate exchanger merits further research under conditions closer to physiological.