Spongy degeneration in the central nervous system of domestic animals. Part II: Chemical analysis and vascular permeability studies.

Two experiments were completed in which brains and spinal cords from lambs affected with spongy degeneration of the central nervous system (CNS) were analysed for water, sodium and potassium, as measures of cerebral oedema. In a third experiment, lambs with CNS spongy degeneration were tested for permeability of cerebral blood vessels by intravenous injections of Evans blue. The CNS spongy degeneration was produced by poisoning with the hepatotoxic pyrrolizidine alkaloid lasiocarpine. In the first experiment, 2 male lambs were poisoned by lasiocarpine and a third injected with saline alone. One lamb injected with lasiocarpine showed widespread spongy changes in the CNS and the other 2 showed normal brains. In the second experiment, 5 males lambs were poisoned by lasiocarpine and 5 were injected with saline. Three of the 5 poisoned lambs showed widespread spongy changes, a fourth showed minor vascuolation and the remaining 6 had normal brains...