Galanin attenuates β-amyloid (Aβ) toxicity in rat cholinergic basal forebrain neurons

In brains of Alzheimer's disease (AD) patients, expression of the neuropeptide galanin is significantly upregulated and galanin-immunoreactive fibers hypertrophy and hyperinnervate cholinergic neurons of the basal forebrain. However, the role of galanin in AD, whether it is detrimental or neuroprotective, remains controversial. In this study, using primary cultured neurons from the rat basal forebrain, we show that pretreatment with galanin protects cholinergic neurons against β-amyloid-induced apoptotic cell death as judged by visual observation, MTT assay, Live/dead cell assay, TUNEL and cleaved caspase-3 staining. These effects are mimicked by the galanin receptor 2 (GALR2) agonist, AR-M1896. Western blot analysis revealed Aβ-induced decrease in phospho-PKC and phospho-Akt levels was reversed by galanin. Galanin also attenuated cleavage of caspases-3 and -9 following exposure to Aβ. These findings support a neuroprotective role for galanin and may have implications for development of compounds based on this peptide to treat AD.