GABA gamma-aminobutyric cells

In simple terms, messages travel along neurons (nerve cells) in the form of an electrical current that moves from one end of the neuron to its opposite end. The electric current is produced by a flow of sodium ions (Na ") and potassium ions (K ) across the nerve membrane, as shown in the diagram on page 11. When the electrical current reaches the end of the neuron, it causes the release of a chemical known as a neurotransmitter. Some examples of neurotransmitters are acetylcholine, serotonin, dopamine, GABA (gamma-aminobutyric acid), and norepinephrine. 

Twaites, D. T., Basterfield, L., McCleave, P. M. J., Carter, S. M., and Simmons, N. L., Gamma-aminobutyric acid (GABA) transport across human intestinal epithelial (Caco-2) cell monolayers, Brit.J. Pharmacol. 2000, 129, 457-464. 

Figure 1.2 Serotonin is one of the brain s neurotransmitters. This image depicts serotonin transmission between neurons and the drug Ecstasy s effects on that transmission. Serotonin is normally removed from the synapse shortly after being released. Ecstasy blocks this mechanism, increasing the amount of serotonin in the synapse. This causes the postsynaptic neuron to be overstimulated by serotonin. Serotonin is one of many neurotransmitters that nerve cells can secrete. Other common neurotransmitters include dopamine, glutamate, gamma aminobutyric acid (GABA), noradrenaline, and endorphins.

Most of the CNS depressants have similar actions in the brain they enhance the actions of the neurotransmitter gamma-aminobutyric acid (GABA)— neurotransmitters are brain chemicals that facilitate communication between brain cells. GABA works by decreasing brain activity. Although different classes of CNS depressants work in unique ways, it is ultimately their common ability to increase GABA activity that produces a drowsy or calming effect. 

There are dozens of types of neurotransmitters that nerve cells can secrete. One of the main neurotransmitters in the brain is called serotonin. Other common neurotransmitters include dopamine, glutamate, gamma aminobutyric acid (GABA), noradrenaline, and histamine. 

Perhaps the most well-known example is the acetylcholine receptor located on the postsynaptic membrane of the neuromuscular junction49 56 (Fig. 4-1). When bound by acetylcholine molecules, the receptor activates and opens a pore through the cell membrane, thereby increasing the permeability of the muscle cell to sodium.38 56 This action results in depolarization and excitation of the cell because of sodium influx. Another important example of a receptor-ion channel system is the gamma-aminobutyric acid (GABA)-benzodiazepine-chloride ion channel complex found on neuronal membranes in the central nervous sys-... 

Benzodiazepines all bind to a specific binding site on the gamma-aminobutyric acid (GABA) A chloride channel. The GABA chloride channel is a multi-subunit protein complex that is found in the plasma membrane of nerve cells in various parts of the CNS. When the neurotransmitter GABA binds to the chloride channel, the channel opens, allowing the influx of chloride ions into the cell. This causes hyperpolarization of the nerve cell and diminishes its response to excitatory input. The GABAa chloride channel is considered the major inhibitory system to neurotransmission in the CNS. 

Ethanol is a central nervous system (CNS) depressant that initially and selectively depresses some of the most active portions of the brain (reticular activity system and cortex). The mechanism of action most likely involves interference with ion transport at the axonal cell membrane rather than at the synapse, similar to the action of other anesthetic agents. Ethanol can bind directly to the gamma-aminobutyric acid (GABA) receptor in the CNS and cause... 

We have shown that the anthelmintics pyrantel, morantel and levamisole, activate acetylcholine (Ach) receptors on the muscle cell membranes of Ascaris suum and also that the avermectin 22,23-dihydroavermectin Bla (DHAVM) blocks the function of muscle cell gamma-aminobutyric acid (GABA) receptors. In experiments using micro-iontophoresis, the cholinergic anthelmintics were found to act directly on the muscle bag membrane, evoking a depolarizing response. 

Gamma-aminobutyric acid (GABA), glutamic acid decarboxylase (GAD) and the GABA-transporters in Purkinje cells... 

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