ABSTRACT
The brain is a very complex structure; it is the origin of thoughts and actions, has 1011 neurons, with more than 1000-fold more dendrites. The neurons not only interact with each other but also with the surrounding glial cells. Electrical impulses propagate along dendrites and axons to communicate between pre-and postsynaptic functions. It is no wonder that these complex functions in the brain require a constant microenvironment to provide the necessary fuel (oxygen and glucose) and to transport away the waste products. In order to secure a constant microenvironment and to maintain adequate metabolism, it is important to have a precise local regulation of the cerebral circulation. Traditionally, cerebral vascular resistance is regulated by metabolic factors, chemical stimuli, perfusion pressure, and perivascular nerves (1). We have recently reviewed the neuronal messengers in the human cerebral circulation (2), with a focus on large arteries belonging to the circle of Willis and their involvement in cerebrovascular disorders. In this chapter, we focus on intracerebral microvessels and their relation to the control of the microenvironment in the brain.
