Ion Channels And Disease

Cells cannot survive without functional ion channels. It is therefore not surprising that an ever-increasing number of diseases have been found to be associated with defective ion channel function. There are a number of different mechanisms by which this may occur. 1. Mutations in the coding region of ion channel genes may lead to gain or loss of channel function, either of which may have deleterious consequences. For example, mutations producing enhanced activity of the epithelial Na+ channel...

The Cerebral Vasculature

Blood vessels form an extremely rich network in the central nervous system, particularly in the cerebral cortex and subcortical gray masses, whereas the white matter is less densely vascularized (Fig. 1.21) (Duvernoy et al., 1981). The vascular bed is supplied by perforating arteries that arise from a relatively small number of large, peripheral arterial trunks. The main trunks give off smaller cerebral arteries whose branches penetrate the subarachnoidal space, where they divide into many...

Building And Maintaining Nervous System Cells

The functional architecture of neurons comprises many specializations in cytoskeletal and membranous components. Each of these specializations is dynamic, constantly changing and being renewed at a rate determined by the local environment and cellular metabolism. The processes of axonal transport represent a key to understanding neuronal dynamics and provide a basis for exploring neuronal development, regeneration, and neuropathology. Recent advances are important sources of insight into the...

Inherited Peripheral Neuropathies

The peripheral myelin protein-22 (PMP22) is a very hydrophobic glycoprotein and is highly expressed in compact PNS myelin. It has been mapped to the previously defined Tr locus on mouse chromosome 11. Comparison of marker genes on mouse chromosome 11 and human chromosome 17 revealed that PMP22 was also a candidate gene for the most common form of autosomal-dominant demyelinating hereditary peripheral neuropathy in humans, Charcot-Marie-Tooth disease type 1A (CMT1A). Indeed, the entire PMP22...

Hepatic Encephalopathy Is A Disorder Of Astrocyte Function Resulting In A N E U R O P S Y C H I At R I C Syndrome

Astrocyte Reactive Hyperplasia

Hepatic encephalopathy is observed in patients with severe liver failure. The disease can be in one of two forms an acute form, called fulminant hepatic failure, and (2) a chronic form, portosystemic encephalopathy (Plum and Hindfeld, 1976). The neuropsychiatric symptoms of fulminant hepatic failure are delirium, coma, and seizures associated with acute toxic or viral hepatic failure. Patients having portosystemic encephalopathy may present personality changes, episodic confusion, or stupor,...