Brain
The brain is made up of different cellular parts that all react differently.
Neurons
Several types of disorders of the neuronal proteins have been observed. The presence of certain kinds of transporters, channels, and neurotransmitters is increased, although the reasons why and the possible effects are usually unknown.
Astrocytes
It has been observed in patients suffering from HE that a cerebral edema occurs, due to a swelling of the astrocytes. This effect is induced by ammonia and reactive oxygen species. Ammonia is also responsible for a change in the pH and an increase in calcium (Rose et al, 2005). Calcium is important for enzymatic signalling pathways and triggers several reactions such as glutamate release.
Glutamate and Glutamine
Glutamate is an excitatory neural transmitter and is used as a substrate in the enzymatic reaction. In the brain, glutamine synthetase is only found in the astrocytes. It enables the detoxication of cerebral ammonia. However, this protein is susceptible to modification through ROS, which decreases its function. This all results in a vicious circle that further amplifies the damage.
Ammonia
Animal models
