Effects of Acute and Chronic Treatment with Imipramine on 5-Hydroxytryptamine and 5-Hydroxytryptamine Comodulators in Central 5-Hydroxytryptamine Neurons and on Glucocorticoid Receptors in Central Monoaminergic Neurons: a Morphometrical and Microdensitometrical Analysis

Central 5-hydroxytryptamine (5-HT) neurons represent targets of action for antidepressant drugs, as for example is demonstrated by the presence of high densities of [3H]-imipramine binding sites in the nerve cell membranes of the central 5-HT neurons (see Langer and Briley, 1981). Quantitative receptor auto-radiography of [3H] -imipramine binding sites has indicated their presence in the nerve cell membrane of the 5-HT cell bodies, axons and nerve terminals (Fuxe et al., 1983a). The density of [3H]-imipramine binding sites seems particularly high in the 5-HT nerve cell group of the nucleus raphe dorsalis (group B7; Dahlstrom and Fuxe, 1964). In view of the fact that a high secretion of cortisol has been demonstrated in patients with a severe depression (see Carroll, 1984), it is also of particular interest that strong glucocorticoid receptor (GR) immunoreactivity (IR) has been demonstrated in the vast majority of the 5-HT nerve cells of the lower brain-stem of the male rat (Fuxe et ah, 1985a, b; Harfstrand et al., 1986a).