PSY 374 Study Guide - Midterm Guide: Attention Deficit Hyperactivity Disorder, Tryptophan Hydroxylase, Tyrosine Hydroxylase
Document Summary
Tyrosine > tyrosine hydroxylase (th) > l-dopa > amino acid decarboxylase (aadc) > da. Tyrosine > tyrosine hydroxylase (th) > l-dopa > amino acid decarboxylase (aadc) > da > Catecholamine breakdown/inactivation catechol-o-methyltransferase (comt): degrading enzyme breaks down da, ne, and epinephrine. Monoamine oxidase (mao): degrading enzyme breaks down da, ne, and 5-ht (monoamines) homovanillic acid (hva): da metabolite (breakdown product) Catecholamine (da and ne) receptors and receptor subtypes. Da uses five receptor subtypes, d1 to d5. All da receptors are metabotropic: they interact with g proteins and function via second messengers. D1 and d5 are similar (d1-like receptors) D2, d3, and d4 are a separate family (d2-like receptors) D2 receptors function as autoreceptors (regulating membrane k+ channels decreasing transmitter release by shortening the duration of action potentials, reducing ca2+ influx and thus reducing exocytosis) and as postsynaptic receptors interacting with da at the synapse. Nearly all current antischizophrenic drugs are d2 postsynaptic receptor antagonists.
