Validation of the internal reference technique for microdialysis measurements of interstitial histamine in the rat

摘要

The internal reference technique (IRT) was compared with the no net flux method (NFM) as a microdialysis calibration technique for sampling of interstitial histamine in the rat. Microdialysis catheters (polyacrylonitrile, 50 kD cut off) were inserted in liver, muscle, subcutaneous tissue and in an induced adenocarcinoma. Estimated relative recovery with IRT ranged from 23 +- 2% in liver to 30 +- 3% in subcutaneous tissue with and without tumor (p < 0.05). By using the NFM-technique we found similar recovery as compared to the IRT in all tissues studied. Interstitial histamine was up to 3-fold higher than the mean plasma histamine concentration (54 +- 2 nmol/l). Subcutaneous tissue (177 +- 39 nmol/l) and subcutaneous tumor (165 +- 29 nmol/l) exhibited high histamine while liver (65 +- 14 nmol/l) and liver tumor (75 +- 7 nmol/l) had low interstitial histamine concentrations. In conclusion, the IRT was validated against the NFM as a rapid method for histamine measurements in situ in the rat.