Category: Aminosaurs
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Proline and a few other notes
Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group -NH2 but is rather a secondary amine. The secondary amine nitrogen is in the protonated form (NH2+) under biological conditions, while the carboxyl group is in the deprotonated −COO− form. The “side chain” from the α carbon connects to the nitrogen forming a pyrrolidine loop, classifying it…
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Serine
Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH+3 form under biological conditions), a carboxyl group (which is in the deprotonated −COO− form under biological conditions), and a side chain consisting of a hydroxymethyl group, classifying it as a polar amino acid. It can be synthesized in the human body under normal physiological circumstances, making…
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Opioid growth factor receptor
Opioid growth factor receptor, also known as OGFr or the ζ-opioid receptor, is a protein which in humans is encoded by the OGFR gene. The protein encoded by this gene is a receptor for opioid growth factor (OGF), also known as [Met(5)]-enkephalin. The endogenous ligand is thus a known opioid peptide, and OGFr was originally discovered and named as a new opioid receptor zeta (ζ). However it was…
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Leu-enkephalin and Met-enkephalin
Leu-enkephalin is an endogenous opioid peptide neurotransmitter with the amino acid sequence Tyr-Gly-Gly-Phe-Leu that is found naturally in the brains of many animals, including humans. It is one of the two forms of enkephalin; the other is met-enkephalin. The tyrosine residue at position 1 is thought to be analogous to the 3-hydroxyl group on morphine. Leu-enkephalin has agonistic actions at both the μ- and δ-opioid receptors, with significantly greater preference for the…
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Enkephalins
An enkephalin is a pentapeptide involved in regulating nociception (pain sensation) in the body. The enkephalins are termed endogenous ligands, as they are internally derived and bind to the body’s opioid receptors. Discovered in 1975, two forms of enkephalin have been found, one containing leucine (“leu”), and the other containing methionine (“met”). Both are products of the proenkephalin gene. Endogenous opioid peptides There are three well-characterized families of opioid…
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Cells in the APUD system may include Juxtaglomerular cells (JG cells), the renin producing cells in the kidney
Juxtaglomerular cells (JG cells), also known as juxtaglomerular granular cells are cells in the kidney that synthesize, store, and secrete the enzyme renin. They are specialized smooth muscle cells mainly in the walls of the afferent arterioles (and some in the efferent arterioles) that deliver blood to the glomerulus. In synthesizing renin, they play a critical role in the renin–angiotensin system and thus in autoregulation of the kidney. Juxtaglomerular cells secrete renin in…
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The adrenal medulla is the principal site of the conversion of the amino acid tyrosine into the catecholamines; epinephrine, norepinephrine, and dopamine
The adrenal medulla (Latin: medulla glandulae suprarenalis) is part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex. It is the innermost part of the adrenal gland, consisting of chromaffin cells that secrete catecholamines, including epinephrine (adrenaline), norepinephrine (noradrenaline), and a small amount of dopamine, in response to stimulation by sympathetic preganglionic neurons. Structure The adrenal medulla consists of irregularly shaped cells…
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G cells or gastrin cells secrete gastrin. They works in conjunction with gastric chief cells and parietal cells. The peptide hormone bombesin also stimulates gastrin from G cells.
In anatomy, the G cell or gastrin cell, is a type of cell in the stomach and duodenum that secretes gastrin. It works in conjunction with gastric chief cells and parietal cells. G cells are found deep within the pyloric glands of the stomach antrum, and occasionally in the pancreas and duodenum. The vagus nerve innervates the G cells. Gastrin-releasing peptide is released by the post-ganglionic fibers of the vagus nerve onto G cells…
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Pulmonary neuroendocrine cells
Neuroendocrine cells are cells that receive neuronal input (through neurotransmitters released by nerve cells or neurosecretory cells) and, as a consequence of this input, release messenger molecules (hormones) into the blood. In this way they bring about an integration between the nervous system and the endocrine system, a process known as neuroendocrine integration. An example of a neuroendocrine cell is a cell…
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Enterochromaffin (EC) cells aka Kulchitsky cells
Enterochromaffin (EC) cells (also known as Kulchitsky cells) are a type of enteroendocrine cell, and neuroendocrine cell. They reside alongside the epithelium lining the lumen of the digestive tract and play a crucial role in gastrointestinal regulation, particularly intestinal motility and secretion. They were discovered by Nikolai Kulchitsky. EC cells modulate neuron signalling in the enteric nervous system (ENS) via the secretion of the neurotransmitter serotonin and other peptides.…
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Chromaffin cells aka pheochromocytes
Chromaffin cells, also called pheochromocytes (or phaeochromocytes), are neuroendocrine cells found mostly in the medulla of the adrenal glands in mammals. These cells serve a variety of functions such as serving as a response to stress, monitoring carbon dioxide and oxygen concentrations in the body, maintenance of respiration and the regulation of blood pressure. They are in close proximity to pre-synaptic sympathetic ganglia of the sympathetic nervous system,…
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Homovanillic acid (HVC) and Vanillylmandelic acid (VMA)
Homovanillic acid (HVA) is a major catecholamine metabolite that is produced by a consecutive action of monoamine oxidase and catechol-O-methyltransferase on dopamine. Homovanillic acid is used as a reagent to detect oxidative enzymes, and is associated with dopamine levels in the brain. In psychiatry and neuroscience, brain and cerebrospinal fluid levels of HVA are measured as a marker of metabolic stress caused by 2-deoxy-D-glucose. HVA presence supports a diagnosis of neuroblastoma and malignant pheochromocytoma. Fasting plasma levels of HVA are known to be…
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Catecholamine (CA)
A catecholamine (abbreviated CA) is a monoamine neurotransmitter, an organic compound that has a catechol (benzene with two hydroxyl side groups next to each other) and a side-chain amine. Fitzgerald, P. A. (2011). “Chapter 11. Adrenal Medulla and Paraganglia”. In Gardner, D. G.; Shoback, D. (eds.). Greenspan’s Basic & Clinical Endocrinology (9th ed.). New York: McGraw-Hill. Retrieved October 26, 2011. Catechol, not to be confused with Catechin which is also sometimes called catechol, can be either…
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What is Immunoprecipitation (IP)?
Immunoprecipitation (IP) is a technique used to enrich protein antigens from a complex mixture using specific antibodies. To carry out an IP, antibodies must be coupled to a solid substrate, such as agarose resin or magnetic beads, to allow for purification of the target antigens. Immunoprecipitation (IP) is the technique of precipitating a protein antigen out of solution using an antibody that…
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Gastric inhibitory peptide aka GIP and receptors
Gastric inhibitory polypeptide or gastric inhibitory peptide also known as glucose-dependent insulinotropic polypeptide abbreviated as GIP, is an inhibiting hormone of the secretin family of hormones. While it is a weak inhibitor of gastric acid secretion, its main role is to stimulate insulin secretion. GIP, along with glucagon-like peptide-1 (GLP-1), belongs to a class of molecules referred to as incretins. Synthesis and transport GIP is derived from a 153-amino acid proprotein encoded by…
