Neurotransmitters are endogenous chemicals that enable neurotransmission. It is a type of chemical messenger which transmits signals across a chemical synapse, such as a neuromuscular junction, from one neuron to another "target" neuron, muscle cell, or gland cell. Neurotransmitters are released from synaptic vesicles in synapses into the synaptic cleft, where they are received by neurotransmitter receptors on the target cells. Many neurotransmitters are synthesized from simple and plentiful precursors such as amino acids, which are readily available from the diet and only require a small number of biosynthetic steps for conversion. Neurotransmitters play a major role in shaping everyday life and functions. Their exact numbers are unknown, but more than 200 chemical messengers have been uniquely identified.
Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group connected to an aromatic ring by a two-carbon chain (such as -CH2-CH2-). Examples are dopamine, serotonin and epinephrine.
The ventricular system is a set of four interconnected cavities (ventricles) in the brain, where the cerebrospinal fluid (CSF) is produced. Within each ventricle is a region of choroid plexus, a network of ependymal cells involved in the production of CSF. The ventricular system is continuous with the central canal of the spinal cord, allowing for the flow of CSF to circulate. All of the ventricular system and the central canal of the spinal cord are lined with ependyma, a specialised form of epithelium.
The raphe nuclei are a moderate-size cluster of nuclei found in the brain stem. They have 5-HT1 receptors which are coupled with Gi/Go protein inhibiting adenyl cyclase. They function as autoreceptors in brain and decreases release of serotonin. The antianxiety drug Buspirone act as partial agonist. Selective serotonin reuptake inhibitor (SSRI) antidepressants are believed to act in these nuclei, as well as at their targets.
The locus coeruleus is a nucleus in the pons of the brainstem involved with physiological responses to stress and panic. It is a part of the reticular activating system.
The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. The reticular formation is not anatomically well defined because it includes neurons located in different parts of the brain. The neurons of the reticular formation make up a complex set of networks in the core of the brainstem that extend from the upper part of the midbrain to the lower part of the medulla oblongata. The reticular formation includes ascending pathways to the cortex in the ascending reticular activating system (ARAS) and descending pathways to the spinal cord via the reticulospinal tracts of the descending reticular formation.
In the human brain, the superior cerebellar peduncle is a paired structure of white matter that connects the cerebellum to the midbrain. It consists mainly of efferent fibers, the cerebellothalamic tract that runs from a cerebellar hemisphere to the contralateral thalamus, and the cerebellorubral tract that runs from a cerebellar hemisphere to the red nucleus. It also contains afferent tracts, most prominent of which is the ventral spinocerebellar tract. Other afferent tracts are the trigeminothalamic fibers, tectocerebellar fibers, and noradrenergic fibers from the locus coeruleus. The superior peduncle emerges from the upper and medial parts of the white matter of each hemisphere and is placed under cover of the upper part of the cerebellum.
Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as a hormone and neurotransmitter. The name "noradrenaline", derived from Latin roots meaning "at/alongside the kidneys", is more commonly used in the United Kingdom; in the United States, "norepinephrine", derived from Greek roots having that same meaning, is usually preferred. "Norepinephrine" is also the international nonproprietary name given to the drug. Regardless of which name is used for the substance itself, parts of the body that produce or are affected by it are referred to as noradrenergic.
Amiflamine (FLA-336) is a reversible inhibitor of monoamine oxidase A (MAO-A), thereby being a RIMA, and, to a lesser extent, semicarbazide-sensitive amine oxidase (SSAO), as well as a serotonin releasing agent (SRA). It is a derivative of the phenethylamine and amphetamine chemical classes. The (+)-enantiomer is the active stereoisomer.
Noradrenergic cell group A1 is a group of cells in the vicinity of the lateral reticular nucleus of the medullary reticular formation that label for norepinephrine in primates and rodents. They are found in the ventrolateral medulla in conjunction with the adrenergic cell group C1.
Noradrenergic cell group A2 is a group of cells in the vicinity of the dorsal motor nucleus of the vagus nerve in the medulla that label for norepinephrine in primates and rodents.
Noradrenergic cell group A5 is a group of cells in the vicinity of the superior olivary complex in the pontine tegmentum that label for norepinephine in primates, rodents and other mammals.
Noradrenergic cell group A6 is a group of cells fluorescent for noradrenaline that are identical with the locus ceruleus, as identified by Nissl stain.
Noradrenergic cell group A6sc is a group of cells fluorescent for norepinephrine that are scattered in the nucleus subceruleus of the macaque.,
Noradrenergic cell group A7 is a group of cells fluorescent for norepinephrine that is located in the pontine reticular formation ventral to the superior cerebellar peduncle of the pons in rodents and in primates.
Noradrenergic cell group Acg is a group of cells fluorescent for norepinephrine that are located in the central gray of the midbrain at the level of the trochlear nucleus in the squirrel monkey (Saimiri) and to a lesser degree in the macaque.
Dopaminergic cell groups are collections of neurons in the central nervous system that synthesize the neurotransmitter dopamine. In the 1960s, dopamine neurons were first identified and named by Annica Dahlström and sv:Kjell Fuxe, who used histochemical fluorescence. The subsequent discovery of genes encoding enzymes that synthesize dopamine, and transporters that incorporate dopamine into synaptic vesicles or reclaim it after synaptic release, enabled scientists to identify dopaminergic neurons by labeling gene or protein expression that is specific to these neurons.
Serotonergic cell groups refer to collections of neurons in the central nervous system that have been demonstrated by histochemical fluorescence to contain the neurotransmitter serotonin (5-hydroxytryptamine). Since they are for the most part localized to classical brainstem nuclei, particularly the raphe nuclei, they are more often referred to by the names of those nuclei than by the B1-9 nomenclature. These cells appear to be common across most mammals and have two main regions in which they develop; one forms in the mesencephlon and the rostral pons and the other in the medulla oblongata and the caudal pons.
