A NOVEL HINGE SYSTEM AND INCUBATION CHAMBER FOR EMULSION-COATED COVERSLIP AUTORADIOGRAPHY

We describe an emulsion-coated coverslip autoradiographic technique fo r large (50 x 50 mm) sections of monkey or human brain. The technique uses adhesive-backed, teflon-reinforced aluminum foil as a flexible hi nge that allows the coverslip to swing away from the slide so that the emulsion and tissue can be processed independently. We also describe a plexiglas incubation chamber that allows two slides with coverslips folded away to be processed back-to-back in 5 ml of reagent solution. In general use, the chamber minimizes the volume of solution needed to cover large slide-mounted sections and is ideal for radioligand or im munohistochemical reactions that use expensive reagents. For autoradio graphy, the chamber greatly facilitates independent processing of the emulsion and tissue section. Together, the foil-hinge method and incub ation chamber virtually eliminate the major technical pitfalls of prev ious emulsion-coated coverslip methods. Moreover, they facilitate comb ination of histochemical or immunocytochemical staining with autoradio graphic localization of neurotransmitter receptors in the same tissue section. This is demonstrated by thioflavin S staining of neuritic pla ques and tangles and autoradiographic localization of serotonin 1A rec eptors in sections of Alzheimer disease brain.