Effects of local anesthetics on aerobic and anaerobic metabolism of the dental pulp.

Pulps from rat incisor have been dissected out and the respiratory activity in the tissues has been measured in a Gilson respirometer (modified Warburg technique). Local anesthetics lidocain (xylocain) and prilocain (citanest) in concentrations 2.5%, 5%, and 10% have been added to the medium. Effects on the membrane permeability i.e. on the potassium-sodium pump has been studied using incubation at 37 degrees C in 24NaCl. The influx of 24Na has been registered in a scintillation counter. The anaerobic respiratory activity has been studied determining lactate dehydrogenase activity with a spectrophotometric technique. The results show that the concentrations of local anesthetics in the medium of 5% and 10% caused a significantly lower respiratory activity of the cells in the dental pulp. This was not the case in the concentration 2.5%. The isotope studies show a decreased uptake in all concentrations indicating a depression of the potassium-sodium pump activity. The lactate dehydrogenase activity was significantly lower in all concentrations of local anesthetics.