Innervation of cerebral blood vessels: Morphology, plasticity, age-related, and Alzheimer's disease-related neurodegeneration

The light microscopical and ultrastructural morphology of the innervation o f the major cerebral arteries and pial vessels is described, including the origins of the different groups of nerve fibres and their characteristic ne urotransmitter phenotype. Species and region specific variations are descri bed and novel data regarding the parasympathetic innervation of cerebral ve ssels are presented. The dynamic nature, or plasticity, of cerebrovascular innervation is emphasized in describing changes affecting particular subpop ulations of neurons during normal ageing and in Alzheimer's disease. The mo lecular controls on plasticity are discussed with particular reference to t arget-associated factors such as the neurotrophins and their neuronal recep tors, as well as extracellular matrix related factors such as laminin. Hypo theses are presented regarding the principal extrinsic and intrinsic influe nces on plasticity of the cerebrovascular innervation. (C) 2001 Wiley-Liss, Inc.