___*PEPTIDE TYPES*___
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(there are at least 100 neuro-peptides in human body)
(and probably hundreds more to be discovered)
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*”neuro-peptides” are small ‘protein-like molecules’ (called ‘peptides’) used by ‘neurons’ to communicate with each other*
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(they are ‘neuronal signaling molecules’ that influence the ‘activity’ of the ‘brain’ and the ‘body’ in specific ways)
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(different ‘neuropeptides’ are involved in a wide range of ‘brain functions’, including…)
‘analgesia’
‘reward’
‘food intake’
‘metabolism’
‘reproduction’
‘social behaviors’
‘learning’
‘memory’
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(‘neuropeptides’ are related to ‘peptide hormones’, and in some cases ‘peptides’ that function in the ‘periphery’ as ‘hormones’ also have ‘neuronal functions’ as ‘neuropeptides’)
(the distinction between ‘neuropeptide’ and ‘peptide hormone’ has to do with the ‘cell types’ that ‘release’ and ‘respond to’ the ‘molecule’; ‘neuropeptides’ are secreted from ‘neuronal cells’ (primarily ‘neurons’ but also ‘glia’ for some ‘peptides’) and ‘signal’ to ‘neighboring cells’ (primarily ‘neurons’))
(in contrast, ‘peptide hormones’ are secreted from ‘neuroendocrine’ cells and travel through the ‘blood’ to ‘distant tissues’ where they evoke a ‘response’)
(both ‘neuropeptides’ and ‘peptide hormones’ are synthesized by the same sets of ‘enzymes’, which include ‘prohormone convertases’ and ‘carboxypeptidases’ that selectively ‘cleave’ the ‘peptide precursor’ at specific ‘processing sites’ to generate the ‘bioactive peptides’)
(‘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’)
(‘neurons’ use many different ‘chemical signals’ to communicate ‘information’ (including ‘neurotransmitters’ / ‘peptides’ / ‘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’ (such as ‘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’)
(many ‘populations’ of ‘neurons’ have distinctive ‘biochemical phenotypes’)
(for example, in one ‘subpopulation’ of about ‘3000 neurons’ in the ‘arcuate nucleus’ of the ‘hypothalamus’, 3 ‘anorectic peptides’ are ‘co-expressed’) –>
‘α-melanocyte-stimulating hormone’
(α-MSH)
‘galanin-like peptide’
‘cocaine-and-amphetamine-regulated transcript’
(CART)
(…and in another ‘subpopulation’, 2 ‘orexigenic peptides’ are ‘co-expressed’) –>
‘neuropeptide Y’
‘agouti-related peptide’
(AGRP)
(these are not the only ‘peptides’ in the ‘arcuate nucleus’)
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(the following ‘peptides’ are also expressed in ‘subpopulations’ of ‘arcuate neurons’…)
‘β-endorphin’
‘dynorphin’
‘enkephalin’
‘galanin’
‘ghrelin’
‘growth-hormone releasing hormone’
‘neurotensin’
‘neuromedin U’
‘somatostatin’
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(these ‘peptides’ are all released centrally and act on other ‘neurons’ at specific ‘receptors’)
(the ‘neuropeptide Y neurons’ also make the classical inhibitory neurotransmitter ‘GABA’)
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(‘invertebrates’ also have many ‘neuropeptides’) –>
(‘CCAP’ regulates ‘heart rate’)
(‘allatostatin’ and ‘proctolin’ regulate ‘food intake’ and ‘growth’)
(‘bursicon’ controls ‘tanning’ of the ‘cuticle’)
(‘corazonin’ has a role in ‘cuticle pigmentation’ + ‘moulting’)
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(‘peptide signals’ play a role in ‘information processing’ that is different from that of ‘conventional neuro-transmitters’, and many appear to be particularly associated with specific ‘behaviors’)
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(for example, ‘oxytocin’ + ‘vasopressin’ have ‘striking’ + ‘specific’ effects on ‘social behaviors’, including ‘maternal behavior’ + ‘pair bonding’)
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*👨🔬🕵️♀️🙇♀️*SKETCHES*🙇♂️👩🔬🕵️♂️*
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💕💝💖💓🖤💙🖤💙🖤💙🖤❤️💚💛🧡❣️💞💔💘❣️🧡💛💚❤️🖤💜🖤💙🖤💙🖤💗💖💝💘
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*🌈✨ *TABLE OF CONTENTS* ✨🌷*
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🔥🔥🔥🔥🔥🔥*we won the war* 🔥🔥🔥🔥🔥🔥