A new method of preparing human whole brain sections for in vitro receptor autoradiography

In vitro receptor autoradiography is a widely used technique for determining the distribution of radioligand binding sites. By using this technique it is possible to investigate alterations in receptor number and affinity caused by trauma or a disease state. To date, however, the largest sections prepared for in vitro autoradiography have been from single human hemispheres, with the adjacent hemisphere being used for neuropathological investigations. Therefore, a method for cutting large cryosections of human whole brain tissue is described. Whole brains obtained less than 2 days postmortem were frozen at -80 degrees C. 1.5-2 cm coronal slices were cut from the brain and embedded and frozen in a carboxymethylcellulose solution. Sections 40 microm in size were sliced from the frozen block at -16 degrees C in a whole body cryostat. The sections were lifted by means of a nylon membrane backing material and subsequently incubated with tritiated ligand to produce autoradiograms of each whole brain coronal section. [(3)H]paroxetine was used in the present study as an example.