Identifying the direct effects of ammonia on the brain.
Metab Brain Dis
; 24(1): 95-102, 2009 Mar.
Article
en En
| MEDLINE
| ID: mdl-19104924
Elevated concentrations of ammonia in the brain as a result of hyperammonemia leads to cerebral dysfunction involving a spectrum of neuropsychiatric and neurological symptoms (impaired memory, shortened attention span, sleep-wake inversions, brain edema, intracranial hypertension, seizures, ataxia and coma). Many studies have demonstrated ammonia as a major player involved in the neuropathophysiology associated with liver failure and inherited urea cycle enzyme disorders. Ammonia in solution is composed of a gas (NH(3)) and an ionic (NH(4) (+)) component which are both capable of crossing plasma membranes through diffusion, channels and transport mechanisms and as a result have a direct effect on pH. Furthermore, NH(4) (+) has similar properties as K(+) and, therefore, competes with K(+) on K(+) transporters and channels resulting in a direct effect on membrane potential. Ammonia is also a product as well as a substrate for many different biochemical reactions and consequently, an increase in brain ammonia accompanies disturbances in cerebral metabolism. These direct effects of elevated ammonia concentrations on the brain will lead to a cascade of secondary effects and encephalopathy.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Encéfalo
/
Encefalopatía Hepática
/
Hiperamonemia
/
Amoníaco
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Metab Brain Dis
Asunto de la revista:
CEREBRO
/
METABOLISMO
Año:
2009
Tipo del documento:
Article
País de afiliación:
Canadá
Pais de publicación:
Estados Unidos