The effects induced on the discharge of subthalamic spontaneously active neurons by inhibiting the enzyme nitric oxide synthase was studiedin two groups of urethane-anesthetized rats. In the first group of animals (n = 10), the activity of subthalamic single units was recorded before andafter the systemic administration of 7-nitro-indazole (7-NI, 50 mg/kg i.p.), a selective inhibitor of neuronal nitric oxide synthase. In the secondgroup of rats (n = 15), N-nitro-l-arginine methyl ester (L-NAME), another inhibitor of nitric oxide synthase, was iontophoretically administeredwhile performing single unit extracellular recordings. The activity of most tested spontaneously discharging neurons (8/10) was influenced by7-NI administration, which always caused a statistically significant decrease in the firing rate of the responsive cells. In contrast, the iontophoreticadministration of L-NAME, although influencing many cells (24/32), did not have univocal effects: in fact, 18 cells were inhibited while 6 neuronswere excited in a statistically significant manner.We hypothesize that nitric oxide neurotransmission could exert a tonic modulatory influence uponspontaneously discharging subthalamic neurons, with a prevalent excitatory effect.
|Numero di pagine||5|
|Stato di pubblicazione||Published - 2006|
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