engleski

Modulation of immune response produced by the damage of cholinergic projections to neocortex in rats

The major source of extrinsic cholinergic innervation of the cerebral cortel in rats are magnocellular neurons of the basal forebrain, lying ventrally and medially to the globus pallidus. They are analogous to the nucleus basalis of Meynert (NB) in primates and their damage leads to the development of senescence related cognitive disorders similar to senile dementia of Alzheimer type in man. To establish the possible involvement of these structures in control of immune responsiveness, in this study we analysed the antibody and cell mediated immunity in rats subjected to bilateral electrolytic lesions of NB. For this purpose (A0xDA)F1 male rats aged 4 months were used. The coordinates for bilateral stereotaxic lesions were 1.8 mm anterior, 2.5 mm lateral to the bregma and 7 mm below the dura. Electrolysis was performed unipolary at the anode with 10 mA. In sham lesioned rats, the electrode was lowered into the NB, but without turning on the current. Ten days later these operated rats and a group of intact animals were sensitized with sheep red blood cells (SRBC) or transplanted with the skin of Y strain of rats. At the end of experiment the site of lesion was histologically verified. The results revealed that bilateral electrolytic lesions of NB did not influence significantly the generation of plaque forming cells in spleen, but produced an enhancement of graft survival. The result was highly significant versus intact control (15.8±0.4 and 12.8±0.5 days, respectively, p<0.001), but nonsignificant versus sham operated rats (14.8±0.3 days), because implantation of the electrode in NB alone resulted also in prolongation of graft survival. The data suggest that cholinergic neurons of basal forebrain might be involved in the control of cellular type of immune response.

nucleus basalis lesion; stereotaxy; immune response; plaque forming cells; graft; rat

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