Effect of microwave irradiation on monoamine metabolism in dissected rat brain.

The effect of 5 kW microwave irradiation on monoamine metabolism was investigated in dissected regions of rat brain. Concentrations of intracerebral monoamines and their metabolites were simultaneously determined by means of high performance liquid chromatography with electrochemical detection. The concentrations of noradrenaline, dopamine and 5-hydroxytryptamine were reduced by a 0.5 s irradiation in comparison with those of decapitated animals. When the duration of irradiation was prolonged by 1.5 s, on the other hand, the levels of monoamines were increased. The changes of metabolite concentrations were generally opposite direction for those of parent transmitters. These findings suggest that the microwave irradiation affects those concentrations and that a 1.5 s irradiation is recommended in order to completely inactivate the corresponding enzyme prior to the simultaneous determination of monoamines' related substances in dissected brain regions.