Muscarinic therapies in Alzheimer's disease; from palliative treatments to disease modification.
Cholinergic therapies for Alzheimer's disease (AD) have been developed following painstaking neuropathological and neurochemical studies. Drugs based upon this approach are in development and it is hoped that these compounds will be of some use as palliative therapy. However, increasing evidence from molecular biology suggests that increasing cholinergic neurotransmission might not only alter cognition but also modify disease progression. The evidence that muscarinic-induced increases in protein kinase C activity favourably alter amyloid precursor protein metabolism and tau phosphorylation is reviewed. A unifying hypothesis of AD pathogenesis brings together plaque and tangle formation, suggesting that cholinergic therapies in development may have far-reaching implications as treatments for AD. (Int J Psych Clin Pract 1997; 1: 15-20).