2-Deoxyglucose uptake in the rat visual system following pupil dilation with atropine

The 2-deoxyglucose (2-DG) technique was used to assess rat visual system metabolic activity after topical eye application of atropine sulfate. After one pupil had been dilated with atropine, the alert and freely moving rats were surrounded by a montage of horizontal and vertical, black and white, square wave gratings of varying spatial frequencies during the 45 min 2-DG uptake period. Autoradiographic analysis of interhemispheric differences in 2-DG uptake revealed that metabolic activity was less in all primary visual structures lying contralateral to, and primarily fed by, the treated eye. The depression was most evident in the dorsal lateral geniculate nucleus, the lateral posterior nucleus and the superior colliculus. These findings urge caution in the use of atropine in studies of rat visual system metabolic activity.