AF64A AFFECTS SEPTAL CHOLINE-ACETYLTRANSFERASE BUT NOT PARVALBUMIN-IMMUNOREACTIVE CELLS

Rats received bilateral intracerebroventricular (ICV) infusions of eit her AF64A (1.5 nmol/ventricle; n = 9) or vehicle (3.0 mu l/ventricle; n = 7). Four weeks later, the animals were anesthetized and their brai ns processed to visualize and quantify choline acetyltransferase (ChAT ) immunoreactive (IR) and parvalbumin-IR GABAergic neurons in the sept al complex by immunocytochemistry (PAP method). AF64A significantly re duced the number of ChAT-IR perikarya in the medial septum (28%), vent ral limb of the diagonal band of Broca (30%), and horizontal limb of t he diagonal band of Broca (20%), but did not affect the number of parv albumin-containing GABAergic neurons in any of the septal subdivisions . These results provide further evidence that AF64A is a selective cho linotoxin.