Nitric oxide-active compounds modulate the intensity of glutamate-evoked responses in the globus pallidus of the rat

Aim The effects of local applied NO-active compounds on glutamate (GLU)-evoked responses were investigated in globus pallidus (GP) neurons. Main methods Extracellularly recorded single units from anesthetized rats were treated with GLU before and during the microiontophoretic application of S-nitrosoglutathione (SNOG), a NO donor, and Nω-nitro-l-arginine methyl ester (L-NAME), a NOS inhibitor. Key findings Most GP cells were excited by SNOG whereas administration of L-NAME induced decrease of GP neurons activity. Nearly all neurons responding to SNOG and/or L-NAME showed significant modulation of their excitatory responses to the administration of iontophoretic GLU. In these cells, the changes induced by NO-active drugs in the magnitude of GLU-evoked responses were used as indicators of NO modulation. In fact, when a NO-active drug was co-iontophoresed with GLU, significant changes in GLU-induced responses were observed: generally, increased magnitudes of GLU-evoked responses were observed during SNOG ejection, whereas the administration of L-NAME decreased responses to GLU. Significance The results suggest that the NO-active drugs modulate the response of GP neurons to glutamatergic transmission. Nitrergic modulation of glutamatergic transmission could play an important role in the control of GP bioelectric activity, considered a fundamental key in the BG function.