Ozone produces functional deficits in the rat visual pathway

The effects of ozone (O-3) have been studied mainly in reference to the respiratory pathways, though some reports have shown that this gas produces noxious effects in brain. The aim of the present work was to study the O-3 effects on the central nervous system, focusing on the visual pathway by means of visual evoked potentials technique recording in the visual cortex and the lateral geniculate nucleus of rats exposed to three different concentrations of O-3 (0.75, 1.5 and 3.0 ppm). Our results showed that P1, N1 and P2 components were significantly delayed in the visual cortex and lateral geniculate nucleus in those rats exposed to 3.0 ppm of O-3. Moreover, the N1 component in the visual cortex was also affected even under exposure to 1.5 ppm of O-3 Results suggest that O-3 exposure affects the conduction mechanisms and synaptic excitability of the visual pathway. It is known that inhalation of O-3 produce a cascade of ozonation products capable of producing lipid peroxidation in the brain. Unevenness of some neurotransmitters has also been referred in animals exposed to this gas. Thus we consider that the delay found in the primary components of the visual evoked potentials could obey to a neurochemical disorder produced by O-3 inhalation. (C) 1997 Elsevier Science Ireland Ltd.