Cholinergic Nervous Pathways in the Forebrain

Abstract

IN a previous communication¹ we described the use of a modified Koelle technique to produce selective staining of certain nuclei and tracts in the rat hindbrain. We have applied recently a similar method to the forebrain of normal animals and after transcortical lesions performed with an ophthalmic knife or cautery. The brains were removed after perfusion with 10 per cent formol saline, and 5–6 mm. transverse slices were afterwards fixed in the same fluid in the cold. To facilitate cutting, the tissue after fixation was soaked in 20 per cent alcohol, or embedded in an alginate gel according to a technique to be described elsewhere. The various media used for incubation contained either acetylthiocholine or butyrylthiocholine as substrates, with or without the addition of 10⁻⁴ M ethopropazine as a pseudocholinesterase inhibitor.