[Quantitative histochemical investigations on the demonstration of soluble and membrane bound acetylcholinesterase in the optic tectum of the rudd (Scardinius erythrophthalmus)].

With the aid of the method of Karnovsky and Roots (1964) which was adapted to the semi-permeable membrane technique and a scanning recording method the relative activity of soluble and membrane bound AChE as well as the influence of fixation with 5% paraformaldehyde on the enzyme activity was investigated quantitative-histochemically in the tectum opticum of the rudd. Approximately 38% of the AChE activity which can be demonstrated in the whole tectum opticum on native untreated cryostat sections are puffer-soluble and only 68% are detectable after fixation. The influence of both puffer and fixation pretreatment is different in the several layers of this brain structure.