Abstract

Introduction

Materials & Methods

Results

Discussion & Conclusion

References

Discussion
Board

Neurotransmitter transporters terminate the action of released neurotransmitter by reuptake. NO has been shown to inhibit uptake of dopamine (DA) and glutamate (glu) in a dose-, time- and temperature dependent fashion in synaptosomes. Inhibition of transporters for some neurotransmitters in brain by NO may be a new type of transynaptic retrograde regulation mechanism for uptake regulation. The present study was undertaken to study the effects of in-vivo NOS inhibition on ex-vivo dopamine and glutamate uptake. Male Sprague Dawley rats were injected with N Nitro-L-arginine (50 mg/kg) or saline and decapitated at various times post-injection (5, 10, 15, 30, 60, 120 min); 3H-DA and 3H-Glu uptake and stable metabolites of NO (NO2+NO3) were determined in synaptosomes prepared from the striatum and hippocampus. Our results show a significant facilitation of both DA and Glu uptake at 15 min post-injection, when the total NO2+NO3 levels also start to fall. However, while lower NO2+NO3 levels persist up to 120 minutes, the facilitation of transport does not accompany this decline, implying a possible compensatory mechanism. Our results suggest that NOS inhibition and the subsequent lowering of brain NO levels result in a transient facilitation of DA and glu uptake in rat striatum and hippocampus, respectively.

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Presentation Number SAkoylu0147
Keywords: nitric oxide, dopamine, glutamate, transport, uptake