Contribution of the Dorsal Noradrenergic Bundle to the Effect of Amphetamine on Acetylcholine Turnover. In: Hanin I, editor. Dynamics of Cholinergic Function. Boston: Springer US; 1986. pp. 991-8. [DOI: 10.1007/978-1-4684-5194-8_97]

Direct catecholaminergic-cholinergic interactions in the basal forebrain. I. Dopamine-beta-hydroxylase- and tyrosine hydroxylase input to cholinergic neurons

Immunocytochemical double-labeling techniques were used at the light and electron microscopic levels to investigate whether dopamine-beta-hydroxylase and tyrosine hydroxylase-containing axons contact basal forebrain cholinergic neurons. Dopamine-beta-hydroxylase- and tyrosine hydroxylase-positive fibers and terminals were found in close proximity to cholinergic neurons throughout extensive basal forebrain areas, including the vertical and horizontal limb of the diagonal band nuclei, the sublenticular substantia innominata, bed nucleus of the stria terminalis, ventral pallidum, and ventrolateral globus pallidus. Cholinergic cells in some aspects of the globus pallidus appeared to be contacted by tyrosine hydroxylase-positive but not dopamine-beta-hydroxylase-positive fibers, suggesting dopaminergic input to cholinergic neurons in these regions. Direct evidence for the termination of dopamine-beta-hydroxylase and tyrosine hydroxylase-positive fibers on cholinergic neurons was obtained in electron microscopic double-immunolabeling studies. Using high magnification light microscopic screening, both qualitative and quantitative differences were noted in the catecholaminergic innervation of forebrain cholinergic neurons. For example, while many cholinergic neurons were in close proximity to single dopamine-beta-hydroxylase-positive varicosities, others, particularly those located in the substantia innominatabed nucleus of the stria terminalis continuum, were apparently contacted by labeled fibers in repetitive fashion. The findings of the present study, together with our preliminary biochemical experiments (Zaborszky et al. [1993] Prog. Brain Res. 98:31-49) suggest that catecholaminergic afferents can differentially modulate forebrain cholinergic neurons. Such interactions may be important in learning and memory processes, and their perturbations may contribute to the cognitive decline seen in aging and in disorders such as Alzheimer's and Parkinson's diseases.

6-Hydroxydopamine lesion of the ventral noradrenergic bundle blocks the effect of amphetamine on hippocampal acetylcholine

Rats treated with amphetamine exhibited an increase in hippocampal acetylcholine turnover, as determined by a mass fragmentographic technique. However, administration of amphetamine to rats which had received stereotaxically placed bilateral injections of 6-hydroxydopamine in the ventral noradrenergic bundle 10 days previously did not increase hippocampal acetylcholine turnover. Because the ventral noradrenergic bundle projects to the septal area, it is suggested that amphetamine increases acetylcholine turnover in the hippocampus by an action on noradrenergic neurons in this pathway.