Effect of morphine on brain uracil release in mouse striatum detected by microdialysis

Effect of acute treatment of morphine is associated with neurotransmitter and neuromodulator changes in the brain. A possible relationship between pyrimidines and morphine has also been discussed. Uracil, a common and naturally occurring pyrimidine derivative which found in RNA, has been suggested to modulate many neurotransmitters or neuromodulators, especially in the mature central nervous system. The present study was performed to determine the effect of acutely intraperitoneal morphine treatment on the release of uracil in mouse striatum. The results showed that morphine significantly decreased the release of uracil at the dose of 10 and 20 mg/kg in a dose dependent manner. Naloxone could reverse the morphine-induced reduction of uracil levels in mouse striatum, at the dose of 4 mg/kg, without affecting basal uracil release. The results suggest that the extracellular level of uracil in mouse striatum could be specifically regulated by the centrally acting drugs, such as morphine. However, the pharmacological implications of such regulation should be further evaluated.