Selective age-related changes in neuronal markers and smooth muscle reactivity in cerebrovascular beds of Fischer 344 rats.

Choline accumulation, choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) activities were measured simultaneously in various cerebrovascular beds and brain areas from Fischer 344 rats aged 4.5 and 22 months. A slight (25%) but not significant decrease in choline accumulation was observed concomitantly with a significant increase (187%, p less than 0.

Small pial vessels, but not choroid plexus, exhibit specific biochemical correlates of functional cholinergic innervation.

In an attempt to provide the biochemical foundations for a putative cholinergic innervation of small pial vessels and choroid plexus, we have assessed their ability to specifically accumulate choline, synthesize and release acetylcholine (ACh) in response to depolarization. Our results show that both small pial vessels and choroid plexus avidly accumulate choline via a sodium-dependent mechanism which could be inhibited by hemicholinium-3 (IC50 in pial vessels = 47.8 microM).

Temporal evolution of regional energy metabolism following focal cerebral ischemia in the rat.

Focal cerebral ischemia in the rat was induced by occlusion of the left middle cerebral artery. The temporal evolution of regional energy metabolism was studied over the 14 days consequent to the induction of ischemia in the frontal, cingulate, parietal, and occipital cortices as well as in the striatum. Regional concentrations of adenosine triphosphate (ATP), phosphocreatine, and lactate and, in addition, glucose and the cerebral/plasma glucose ratio (C/P) were measured in the hemispheres both ipsilateral and contralateral to the occlusion.

Neuronal versus endothelial origin of vasoactive acetylcholine in pial vessels.

Functional pial vessels denuded in situ of the endothelial cell layer exhibit a markedly decreased choline uptake capacity (-53%) but integrally preserved choline acetyltransferase (ChAT) activity and acetylcholine (ACh) release mechanisms. These studies demonstrate that endothelial cells possess a specific choline uptake system. However, the unimpaired ChAT activity in denuded pial vessels implies that the endothelial pool of choline is not significantly metabolized into ACh.