RESUMO
OBJECTIVE: Nitric oxide synthesized from L: -arginine via the nitric oxide synthase enzyme family is the main regulatory molecule in many physiological systems. The level of nitric oxide can now be measured in tissues by a direct real-time amperometric method. The effect of electrical stimulation of the upper cervical spine on the arteries that supply the brain and upper extremities has been established by experimental studies, and thus it has begun to be used in clinical practice to increase blood flow in the brain and the peripheral vascular system. The mechanism of this effect is still a subject of research. This is the first report of real-time nitric oxide measurement in living brain and dermal tissue during electrical stimulation of the upper cervical spine. METHODS: Using the amperometric method, nitric oxide levels in frontal subcortical and front foot skin were measured before, during and after electrical stimulation of the upper cervical spine in three groups of rabbits that received infusions of saline solution, 7-aminoguanidine or atropine. RESULTS: By electrical stimulation, tissue nitric oxide levels increased significantly and remained increased during stimulation in the brain and skin. The nitric oxide levels dropped back to normal value 1 min after stimulation was turned off. CONCLUSION: The results we obtained have showed that real-time nitric oxide could also be measured by an amperometric method in living tissues like brain. The effect of stimulation on nitric oxide levels of living tissues disappears immediately when the stimulation is turned off.
