Influence of local injection of 5,7-DHT and 6-OH-DA into the neocortex on learning and exploratory behavior of rats in the open field

Abstract

The features of the exploratory behavior in the open field, of the learning of a conditioned-reflex food-procuring reaction, and of the shift in the level of biogenic amines of the brain was studied in Wistar rats with local injections of the specific neurotoxins 6-hydroxydopamine (6-OH-DA) and 5,7-dihydroxytryptamine (5,7-DHT). It was shown that damage to the structure of the serotoninergic or catecholaminergic systems of the frontal cortex and hippocampus caused by local injection of 6-OH-DA and 5,7-DHT into the neocortex is accompanied by multidirectional changes in the exploratory behavior and learning of the animals.

Chronic stress impairs rat spatial memory on the Y maze, and this effect is blocked by tianeptine treatment.

“…The main target of TIA is the serotonergic system, but other neurotransmitters may be altered as TIA increases extracellular concentrations of dopamine in the striatum and decreases acetylcholine release in the hippocampus (for review, see Wilde & Benfield, 1995). In fact, some have suggested that the pure disruption of the serotonergic system produces little, if any, memory problems in rats (Asin, Wirtshafter, & Fibiger, 1985; Ismailova et al, 1990) but that memory impairments can be detected when other neurotransmitter systems are simultaneously disturbed, such as the cholinergic system (Nilsson, Strecker, Daszuta, & Björklund, 1988; Vanderwolf, 1987), the norepinephrine system (Ricaurte et al, 1993), or systems that send passing fibers through the median raphe (Asin et al, 1985).…”