NEUR 3204 Lecture Notes - Lecture 5: Botulinum Toxin, Muscarine, Fluoxetine

• School: Carleton University
• Department: Neuroscience
• Course: NEUR 3204
• Professor: Patrice Smith

Document Summary

Catecholamine synthesis begins with the amino acid tyrosine. Tyrosine hydroxylase (th) and aromatic amino acid decarboxylase (aadc) are found in neurons that make da: these are enzymes. Neurons that synthesize ne also have dopamine -hydroxylase (dbh). Th is the rate-limiting enzyme in the pathway. It determines the overall rate of da or ne synthesis: determines how much da/ne is generated. After synthesis, catecholamines are packaged into vesicles. A specific transporter in the vesicle membrane recognizes monoamines the vesicular monoamine transporter (vmat). Vmat can be blocked by the drug reserpine. Catecholamines are normally released by exocytosis when a nerve impulse reaches the terminal. Some drugs (example: amphetamine) can stimulate da release at the synapse: promote additional binding, ap promotes release. Reuptake: da and ne move from the synaptic cleft into the nerve terminal via specific membrane transporter proteins. Breakdown of catecholamines by catechol-o-methyltransferase (comt) and monoamine oxidase (mao): da metabolite (breakdown product) in humans is homovanillic acid (hva), located at synapse.