ABSTRACT
We have developed a depression model with various similarities to the human illness, based on the behavioural effects of 2 h restraint stress in the rat, i.e. (a) increased plasma corticosterone during stress, (b) decreased activity 24 h later in an open field, and (c) hypophagia. On repeating the stress each day, adaptation occurs i.e. behaviour becomes normal (Kennett et al., 1985a). Failure to adapt is the depression model. Adaptation was associated with increased postsynaptic 5–HT function as 24 h after repeated stress, components of the 5–HT behavioural syndrome induced by the 5–HT agonist 5–methoxy–N,N–dimethyltryptamine (5–MeODMT) were increased. The hypophagia is not due to stress–induced ulceration (Donohoe et al., 1987) and is of interest as anorexia nervosa may be a manifestation of depression (Brambilla et al., 1985).
