Supravital Staining and Fixation of Brain and Spinal Cord by Intravascular Perfusion

Forty single and 13 combinations of dyes were tested for concomitant supravital staining and fixation of brain and spinal cord of rats, cats and squirrel monkeys by intravascular perfusion in 3 steps: (1) 60 or 80 ml of physiological saline containing 40 mg/100 ml of NaNO₂ as a vasodilator; (2) 250 or 550 ml of stain-fixative solution consisting of either: A—2 parts of dye solution in a concentration from 0.001% to 0.05% dissolved in saline containing 40 mg/100 ml of NaNO₂ and 1 part undiluted formalin; or B—2 parts of dye solution in a concentration from 0.001% to 0.05% dissolved in distilled water acidified with 1.5 ml of glacial acetic acid per 100 ml of water, and 1 part undiluted formalin; and (3) 100 or 150 ml of 6% dextrose in distilled water. Complete staining and fixation was accomplished in 53 min for rats and 41 min for cats and monkeys. Brains and spinal cord were frozen sectioned, and the cut surfaces of the frozen tissue were photographed similar to the procedure described by Gasteiger et al