Effect of choline-containing phospholipids on brain cholinergic transporters in the rat

Abstract

The influence of one week treatment with the choline-containing phospholipids cytidine-5'-diphosphocholine (CDP-choline) and choline alphoscerate (L-alpha-glyceryl-phosphorylcholine) at choline-equivalent doses (CDP-choline: 325 mg/kg/day; choline alphoscerate: 150 mg/kg/day) on vesicular acetylcholine transporter (VAChT), on choline transporter (CHT) and on acetylcholine (ACh) concentrations was investigated in rat frontal cortex, striatum and cerebellum. ACh was assayed by HPLC with electrochemical detection, VAChT by Western blot, ELISA and immunohistochemistry, CHT by Western blot and immunohistochemistry. After CDP-treatment, ACh levels were slightly increased in the frontal cortex, not substantially different in the striatum, and reduced significantly in the cerebellum compared to controls. Choline alphoscerate stimulated significantly the neurotransmitter concentration in the frontal cortex, however, the levels were similar to the controls in both the striatum and cerebellum. In comparison to the controls, VAChT expression following either CDP-choline or choline alphoscerate treatment, was enhanced greatly in the striatum and cerebellum. Also, ELISA measurements for VAChT showed significant increases in all choline alphoscerate treated brain areas. In contrast, in the CDP-choline treated rats the vesicular transporter amount was greater than the control only in the striatum. The cholinergic presynaptic transporters VAChT and CHT play a relevant role in sustaining new ACh synthesis and release. To sum up, CDP-choline and choline alphoscerate stimulated to a different extent the expression of VAChT and CHT primarily in a cognitive area such as frontal cortex. In the lack of novel therapeutic strategies, safe compounds developed since a long time such as the choline-containing phospholipids investigated would merit to be further investigated by new and adequate clinical studies. This for assessing their place if any in pharmacotherapy of dementia disorders characterized by diminished cholinergic tone.