neurotransmitters Flashcards
which 2 aa are NTs?
glycine- inhibitor NT in spinal cord
glutamate - excitatory NT
what is unique about the degradation of NE/epi?
both require methylation (by COMT, SAM) and oxidation (by MAO-A), but the order does not matter
what is the order of reactions of dopamine degradation?
methylation followed by oxidation
final product is homovanillic acid
what do dopamine and serotonin have in common?
the first two steps in the synthesis of each involves hydroxylation with BH4 followed by decarboxylation with PLP
describe the synthesis of GABA in the CNS
GABA is made from glutamate using PLP; however, glutamate uptake in the CNS is low, therefore astroglial cells take up a-ketoglutarate and convert it to glutamate and then glutamine, glutamine travels to neurons and is converted back to glutamate, then converted to GABA
what is the GABA shunt?
GABA transaminase converts GABA + a-ketoglutarate to to glutamate + succinate semialdehyde
what is the fate of succinate semialdehyde?
succinate semialdehyde –> succinate –> aketoglutarate
what is the form of histamine in the periphery vs CNS?
periphery- histamine
CNS- methylhistamine (synthesized by histidine methyltransferase with SAM)
what degrades histamine per location?
peripheral- diamine oxidase
CNS- MAO-B
what are the 2 types of MAO?
MAO-A = serotonin, NE, epi, melatonin
MAO-B = histamine
both work on dopamine equally as well
how are melanin pigments formed?
tyrosine –> dopa quinone (polymerize)»_space; melanin
enzyme is tyrosinase, needs Cu
how are thyroid hormones synthesized?
tyrosine +iodine –> MIT or DIT by tyrosine peroxidase
