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DIA 1 Co-existence of amine and/or peptide transmitters in the vast majority of neurons. DIA 2 Communication of information between neurons is accomplished by movement of chemicals across a small gap called the synapse. Chemicals, called neurotransmitters, are released from one neuron at the presynaptic nerve terminal. Neurotransmitters then cross the synapse where they may be accepted by the next neuron at a specialized site called a receptor. The action that follows activation of a receptor site may be either depolarization (an excitatory postsynaptic potential) or hyperpolarization (an inhibitory postsynaptic potential). A depolarization makes it MORE likely that an action potential will fire; a hyperpolarization makes it LESS likely that an action potential will fire. And for this type of communications Neurons uses amine or peptide transmitters. Peptide: DIA 3 Neuropeptides are small protein-like molecules (peptides) used by neurons to communicate with each other. They are neuronal signaling molecules that influence the activity of the brain and the body in specific ways. Different neuropeptides are involved in a wide range of brain functions, including analgesia, reward, food intake, metabolism, reproduction, social behaviors, learning and memory. DIA 4 Neuropeptides modulate neuronal communication by acting on cell surface receptors. Many neuropeptides are co-released with other small-molecule neurotransmitters. The human genome contains about 90 genes that encode precursors of neuropeptides. At present about 100 different peptides are known to be released by different populations of neurons in the mammalian brain.[2] Neurons use many different chemical signals to communicate information, including neurotransmitters, peptides, and gasotransmitters. Peptides are unique among these cell-cell signaling molecules in several respects. One major difference is that peptides are not recycled back into the cell once secreted, unlike many conventional neurotransmitters (glutamate, dopamine, serotonin). Another difference is that after secretion, peptides are modified by extracellular peptidases; in some cases, these extracellular cleavages inactivate the biological activity, but in other cases the extracellular cleavages increase the affinity of a peptide for a particular receptor while decreasing its affinity for another receptor. These extracellular processing events add to the complexity of neuropeptides as cell-cell signaling molecules. Generally, peptides act at metabotropic or G-protein-coupled receptors expressed by selective populations of neurons. In essence they act as specific signals between one population of neurons and another. Neurotransmitters generally affect the excitability of other neurons, by depolarising them or by hyperpolarising them. Peptides have much more diverse effects; amongst other things, they can affect gene expression, local blood flow, synaptogenesis, and glial cell morphology. Peptides tend to have prolonged actions, and some have striking effects on behaviour. DIA 5 Amine: A catecholamine is a monoamine, an organic compound that has a catechol (benzene with two hydroxyl side groups at carbons) and a side-chain amine. The three catecholamine neurotransmitters: DIA 6 • Norepinephrine (noradrenaline) a neurotransmitter involved in sleep and wakefulness, attention, and feeding behavior, as well as a stress hormone released by the adrenal glands that regulates the sympathetic nervous system. The general function of norepinephrine is to mobilize the brain and body for action. Norepinephrine release is lowest during sleep, rises during wakefulness, and reaches much higher levels during situations of stress or danger, in the so-called fight-or-flight response. In the brain, norepinephrine increases arousal and alertness, promotes vigilance, enhances formation and retrieval of memory, and focuses attention; it also increases restlessness and anxiety. In the rest of the body, norepinephrine increases heart rate and blood pressure, triggers the release of glucose from energy stores, increases blood flow to skeletal muscle, reduces blood flow to the gastrointestinal system, and inhibits voiding of the bladder and gastrointestinal motility. DIA 7 • Epinephrine (adrenaline) an adrenal stress hormone, as well as a neurotransmitter present at lower levels in the brain. Epinephrine, also known as adrenalin or adrenaline, is primarily a medication and a hormone. As a medication it is used for a number of conditions including anaphylaxis, cardiac arrest, and superficial bleeding. Inhaled epinephrine may be used to improve the symptoms of croup. It may also be used for asthma when other treatments are not effective. It is given intravenously, by injection into a muscle, by inhalation, or by injection just under the skin. DIA 8 • Dopamine a neurotransmitter involved in motivation, reward, addiction, behavioral reinforcement, and coordination of bodily movement. In the brain, dopamine functions as a neurotransmitter—a chemical released by neurons (nerve cells) to send signals to other nerve cells. The brain includes several distinct dopamine pathways, one of which plays a major role in reward-motivated behavior. Most types of reward increase the level of dopamine in the brain, and many addictive drugs increase dopamine neuronal activity. Other brain dopamine pathways are involved in motor control and in controlling the release of various hormones. These pathways and cell groups form a dopamine system which is neuromodulatory. Outside the central nervous system, dopamine functions in several parts of the peripheral nervous system as a local chemical messenger. In blood vessels, it inhibits norepinephrine release and acts as a vasodilator (at normal concentrations); in the kidneys, it increases sodium excretion and urine output; in the pancreas, it reduces insulin production; in the digestive system, it reduces gastrointestinal motility and protects intestinal mucosa; and in the immune system, it reduces the activity of lymphocytes. With the exception of the blood vessels, dopamine in each of these peripheral systems is synthesized locally and exerts its effects near the cells that release it. Resources used: https://en.wikipedia.org/wiki/Catecholamine https://en.wikipedia.org/wiki/Biogenic_amine https://www.ncbi.nlm.nih.gov/pubmed/21922398 https://en.wikipedia.org/wiki/Neurotransmitter https://en.wikipedia.org/wiki/Neuropeptide https://en.wikipedia.org/wiki/Peptide http://thebrain.mcgill.ca/flash/i/i_01/i_01_m/i_01_m_ana/i_01_m_ana.html#2 https://faculty.washington.edu/chudler/chnt1.html