Brain GABA balance

In essence, all of the older benzodiazepines that are structurally related to chlordiazepoxide and diazepam are termed 1,4-benzodiazepines. The chemical structure of some commonly used benzodiazepines is shown in Figure 9.2. They enhance the actions of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in the brain. As a consequence, they affect the activities of the cerebellum (concerned with balance and coordination), the limbic areas of the brain and the cerebral cortex (thought and decision making, fine movement control). 

Depletion of glutamate in the glutamine synthetase reaction may have additional effects on the brain. Glutamate and its derivative y-aminobutyrate (GABA see Fig. 22-29) are important neurotransmitters the sensitivity of the brain to ammonia may reflect a depletion of neurotransmitters as well as changes in cellular osmotic balance. ... 

Gamma aminobutyric acid (GABA) The neurotransmitter GABA and its allosteric modulation by benzodiazepines have also been implicated in the biological basis of panic disorder. That is, it appears that the ability of benzodiazepines to modulate GABA is out of balance. This may be due to changes in the amounts of endogenous benzodiazepines (i.e., the brain s own Xanax or Valium-like compound ), or to alterations in the sensitivity of the benzodiazepine receptor itself. 

Recent studies suggest that the brain may contain its own family of valium-like compounds, the P-carbolines. Some of these antagonize GABA function and others enhance it, but all may share a similar ability to inhibit the destruction of the neurotransmitters dopamine, norepinephrine, and serotonin taken together, these effects would tend to produce a mild, relaxed euphoria. The balance of action of these endogenous antianxiety compounds is determined by the genes we inherit from our parents, which control the carbolines produced and probably... 

The amino acids GABA and glutamic acid (glutamate) (Figs. 4 and 5, respectively) are major inhibitory and excitatory neurotransmitters, respectively, in the central nervous system, and a requisite balance between the two operates in normal brain. Aberrations in the functions of one or both of these neurotransmitters have been implicated in the pathogenesis of several neurological and psychiatric disorders, which include depression (36-38). 

The actual requirement for a neuron, whether or not an action potential is accomplished exclusively governed by the achievable equilibrium (or balance) between the prevailing excitatory and inhibitory stimulation. It has been established beyond any reasonable doubt that GABA is solely responsible as the predominant inhibitory transmitter in the brain. The modus operandi are as stated below ... 

In addition to being an excitatory neurotransmitter, glutamate is also a precursor in the synthesis of GABA, the most active inhibitory neurotransmitter in the human brain, illustrating the continual balancing of excitatory and inhibitory neuronal activity. 

Nervous system In one case a high dose of octreotide may have altered the balance between brain dopamine and GABA, and thus caused Parkinson-like symptoms [35" ]. 

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