VOLTAMMETRIC DETECTION OF NITRIC-OXIDE (NO) IN THE RAT-BRAIN - ITS VARIATIONS THROUGHOUT THE SLEEP-WAKE CYCLE

A sensor allowing the specific detection of nitric oxide (NO) is repor ted. Together with differential pulsed voltammetry, it allows the dete ction of a 650 mV signal either in NO solutions or in the rat frontal cortex. The intraperitoneal (i.p.) administration of a NO donor (S-nit rosoglutathione, 20 mg/kg i.p.) increases the signal height (+30%) whi le that of a nitric oxide synthase (NOS) inhibitor like L-nitro-argini ne-p-nitro-anilide (100 mg/kg i.p.), produces its complete disappearan ce in the cortex of anesthetized rats. These results suggest that the 650 mV signal might be NO-dependent. Some other NOS inhibitors have be en found either inefficient (L-nitro-arginine-methyl-ester) or partial ly efficient (7-nitro-indazole) on the signal height. In freely moving rats, also equipped with polygraphic electrodes, the signal measured in the frontal cortex exhibits the highest height during waking. It de creases during slow-wave sleep (-6%) and paradoxical sleep (-9%). (C) 1997 Elsevier Science Ireland Ltd.