Toxic Responses of the Nervous System

Toxic Responses of the Nervous System
Blood-Brain Barrier
The central nervous system (CNS) is protected from the adverse effects of many potential toxicants by an anatomic barrier between the blood and the brain, or a "blood-brain barrier." (Molecules must pass into the cell membranes of endothelial cells in the brain rather than between endothelial cells, as they do in other tissues). The blood-brain barrier also contains xenobiotic transporters that transport some xenobiotics that have diffused through endothelial cells back into the blood. The penetration of toxicants or their metabolites into the nervous system (NS) is related largely to their lipid solubility. The blood-brain barrier is incompletely developed at birth and even less developed in premature infants. This prompts a premature infant exposed to brain injury by toxicants more that later in life.
Energy Requirements
Neurons are highly dependent on aerobic metabolism because they must use this energy to maintain proper ion gradients. The brain is extremely sensitive to even brief interruptions in the supply of oxygen or glucose.
Axonal Transport
Impulses are conducted over great distances at rapid speed, providing information about the environment to the organism in a coordinated manner that allows an organized response to be carried out at a specific site. The transport of intracellular materials over great distances requires ATP.