Neurotoxins that affect central indoleamine neurons

The indoleamme serotonin (5-hydroxytryptamine, 5-HT) was described in the central nervous system (CNS) more than 30 years ago (Amin et al., 1954; Bogdanski et al., 1956; De Robertis, 1964; Twarog and Page, 1953; Zieher and De Robertis, 1963) based on biochemical determinations of this amine in different brain regions. These studies were rapidly followed by the use of histofluorescent microscopy (Anden et al., 1965, 1966, 1967; Dahlstrom and Fuxe, 1964; Fuxe, 1965; Moore et al., 1978; Ungerstedt, 1971) and measurements of the activity of tryptophan hydroxylase and 5-HT uptake (Kuhar et al., 1972). This work was later complemented by anatomical descriptions of the now chemically identified neurotransmitter systems using radioautographic tracing techniques that take advantage of the uptake properties of the 5-HT system (Azmitia, 1978; Azmitia and Segal, 1978; Beaudet and Descarrres, 1981, Parent et al, 1981) as well as by the use of immunocytochemrcal methods with antibodies against 5-HT itself (Steinbusch, 1981, Steinbusch et al , 1978; Steinbusch and Nreuwenhuys, 1983).