Sinapsis

The structure of the synapse
To carry out its function involved in the transmission of information, all chemical synapses are composed of three elements: a presynaptic element, an element postsynaptic and synaptic cleft. The element is presynaptic nerve endings containing and releasing the neurotransmitter, which is stored in synaptic vesicles. The synaptic cleft is a space of about 20-30 nmthick separation between pre-and postsynaptic elements. The postsynaptic element is composed of a plasma membrane in the second neuron facing the synaptic cleft. Although the axon or the soma of a neuron can act as postsynaptic element, the most common are dendritic trunks and dendritic spines. On the inside of postsynaptic membrane is usually a dense material, which leads to the so-calledpostsynaptic density.
From a molecular standpoint, the synapse has a complex organization in both parts of the pre-and postsynaptic binding, and neurochemical and molecular mechanisms specific, which include neurotransmitters, receptors, enzymes synthesis, degradation and regulation, adhesion proteins, receptor anchoring proteins, and so on. Out of this large set of synaptic proteins, neurotransmitters andreceptors are particularly important, since they are the targets of drugs for which therapeutic level acts on brain function.

Neurotransmitters
Today more than 50 known substances that act as neurotransmitters. Such substances include biogenic amines, amino acids, nucleosides and nucleotides or several neuropeptides. In addition, the paper is now accepted gaseous neurotransmitter such asnitrous oxide (NO) and carbon monoxide (CO).

Once synthesized in neurons, neurotransmitters are stored in synaptic vesicles, which release it into the synaptic cleft by a Ca2 +-dependent mechanism. The time elapsed since the release of neurotransmitter from the presynaptic nerve terminal to cause an action on the postsynaptic neuron, which is called the synaptic delay can be variable. The existenceof this variability makes talk of two types of neurotransmission: the rapid neurotransmission and neurotransmission slow. The first refers to immediate action, in milliseconds, while the second refers to a long duration of action and modulating neurotransmitters.

The role of glutamate and GABA
The vast majority of communication between neurons in the CNS is by neurotransmitter amino acids.The amino acids known as neurotransmitters are five: g-aminobutyric acid (GABA), glycine, taurine, glutamic acid and aspartic acid. The first three have predominantly inhibitory effects, while the latter two are usually excitatory. Of these, the most abundant and physiologically more important, are glutamate and GABA.
Glutamate mediates most excitatory synaptic transmission in the brain. Isinvolved in physiological processes as diverse as cell proliferation, apoptosis, cell survival, proliferation of nerve cells, learning and memory, as well as pathological processes such as epilepsy, hypoxia, and ischemic brain injury. Furthermore, also known direct involvement in major neurological degeneration, Alzheimer's disease or Huntington's chorea.
On the other hand, GABA mediates mostinhibitory synaptic transmission in the brain. Other possible functional implications, it is believed that alteration of GABA is involved in processes such coordinated or integrated in relation to motor and cognitive processes, as well as in major neurological and psychiatric disorders, such as the case of Huntington's chorea, the epilepsy, tardive dyskinesia, alcoholism, schizophrenia, sleep disorders andParkinson's disease.

Types of neurotransmitter receptors
To carry out the transmission of information, the neurotransmitter that has been released by the nerve terminal of the presynaptic neuron, it must interact with the postsynaptic neuron. The postsynaptic membrane contains molecules with high affinity to a single neurotransmitter, which are called receptors.
All physiological actions...