Nitric oxide modulates the firing activity of striatal neurons in response to electrical stimulation on the substantia nigra
Phasic dopamine (DA) transmission plays a critical role in the generation of movement. Recent studies suggest that DA may activate nitric oxide (NO)-interneurons in the striatum. NO is a potent modulator of striatal neuronal activity. Thus the potential intermediary role of NO in the modification of striatal firing rate under basal conditions and its response to phasic DA release induced by electrical stimulation of the substantia nigra pars compacta (A9) was examined using in vivo extracellular recordings. Systemic administration of the neuronal nitric oxide inhibitor 7-nitroindazole (7-NI) (EC50 dose, 25mg/kg, i.p.) did not produce any significant effect on the firing rate of striatal neurons under basal conditions or during DA cell burst firing. While the current findings suggest that a partial depletion of NO tone does not affect the firing activity of striatal neurons directly, additional studies performed in identified neurons are necessary to substantiate these conclusions.