Abstract
A method is introduced by which quantitative estimations of changes in amine fluorescence of cortical noradrenaline (NA) terminals can be made using smear preparations (Olson and Ungerstedt, 1970). The method is based on counts performed on photographs using different transmittance gratings. With use of this method it is possible to make comparisons based not only on the number of NA varicosities, but also on the fluorescence intensity of the sampled fields. The method is highly reliable, since the data are in good agreement with biochemical findings as illustrated in experiments using tyrosine-hydroxylase inhibition and 6-hydroxydopamine-induced lesions of the NA pathway to the cortex cerebri.