Effects of tetrahydro-9-aminoacridine on the electrocorticogram of rats with a unilateral lesion of the nucleus basalis magnocellularis.

The effects of tetrahydro-9-aminoacridine (THA) were studied on the electrocortical activity of control rats and of rats with a unilateral lesion of the nucleus basalis magnocellularis (NBM) produced by alpha-amino-3-hydroxy-4-isoxozole propionic acid (AMPA). This lesion almost completely deprived the lesioned hemisphere of its cholinergic innervation. In control rats, THA (10 mg/kg i.p.) increased the amplitude of the slow components of the electrocorticogram (less than 9 Hz). These effects were antagonised by atropine (5 mg/kg i.p.). Lesion of the NBM alone decreased the amplitude of frequencies in the 12-16 Hz frequency band but did not significantly affect the slower frequencies. THA (10 mg/kg) restored the amplitude of the 12-16 Hz activity to the level seen in control rats before THA but did not affect activity in the other frequency bands. The results suggest that THA requires some residual cholinergic innervation in order to exert its effect.