Adenosine measurement by a rapid HPLC-fluorometric method: induced changes of adenosine content in regions of rat brain.

We describe a rapid, sensitive method to determine brain adenosine content by HPLC. Adenosine is first reacted with chloroacetaldehyde to form fluorescent 1,N6-ethenoadenosine. The derivative is then separated from interfering compounds by HPLC on a C18 reverse-phase column and quantitated by fluorometry. We found that adenosine was rather uniformly distributed in nine brain regions of animals killed by microwave radiation. In contrast, there was an increase of adenosine in hippocampus, frontal cortex, and especially striatum of animals killed by decapitation. Moreover, adenosine content increased approximately 10-fold in the thalamus, mesencephalon, and ponsmedulla if the animals were exposed to CO2 for 1 min before they were killed by microwave radiation. Our method should be a useful aid for providing new information about the metabolic and proposed transmitter roles of brain adenosine.