Nimodipine selectively stimulates β-amyloid 1-42 secretion by a mechanism independent of calcium influx blockage

Several lines of evidence indicate that perturbed cellular Ca2+ homeostasis may Play a prominent role in synaptic dysfunction and neuronal death in Alzheimer's disease (AD), suggesting a potential benefit of drugs capable to stabilize Ca2+ homeostasis. We here investigated the effects of a panel of L-type Ca2+ channel antagonists on the secretion of the amyloid beta-peptide (A beta), which abnormally accumulates in the senile plaques of the brain of AD patients. We found that, in primary and immortalized neuronal cells in culture, nimodipine robustly Stimulated secretion (up to about four-fold at 30 mu M) of the highly amyloidogenic 42-residue isoform of A beta (A beta 42). while leaving largely unaffected total A beta secretion, An analogous effect was also observed in vivo, as the administration of a single dose of nimodipine (10 mg/kg i.p.) induced a significant rise of A beta 42 levels in plasma of Tg2576 mice. The effect of nimodipine was independent of blockage of L-type independent, as neither Ca2+ channels and capacitative calcium entry. Accordingly, nimodipine effect was largely Ca2+-independent, as neither depletion nor rise of extracellular Ca2+ abolished it. Hence, by showing that the effect of nimodipme on A beta 42 production is distinct from its ability to block Ca2+-influx pathways, we provide evidence for a previously uncharacterized effect of this long known molecule also used in clinical practice. (C) 2005 Elsevier Inc. All rights reserved.