Biogenic amines Flashcards
How is adrenaline synthesized?
Tyrosine is hydroxylated by tyrosine hydroxylase to DOPA, DOPA is then decarboxylated by DOPA decarboxylase to dopamine, dopamine is hydroxylated by dopamine beta-hydroxylase to NE, NE is then methylated by PNMT to adrenaline
What are similar for dopamine, noradrenaline and adrenaline?
They are catecholamines
What are similar for serotonine and melatonine?
They are indolamines
How are serotonine synthesized?
Tryptophan is hydroxylated by tryptophan hydroxylase to 5HTP, 5HTP is then decarboxylated by 5HTP decarboxylase to 5HT (serotonine)
How are melatonine synthesized?
Synthesized from serotonine in the pineal glands: O-methylated and N-acetylated
How is the catecholamines degraded?
By MAO or COMT: MAO removes the amine-group, and replaces it with an aldehyd-group, COMT methylates the OH-group on the catechol
Which are the two pathways for dopamine in the brain?
The nigrostriatal (from substantia nigra to the stratium) and the mesolimbocortical (from the ventral tegmental area to the prefrontal cortex)
What are some of the functions of dopamine in the brain?
Reward, motivation, pleasure, euphoria, motor functions
Where are most of the serotonine found in the body?
90 % of serotonine are found in the enterochromaffin cells and neurons of the intestine
What are some of the functions of serotonine?
Gastrointestinal motility, appetite, sleep, memory, learning, mood, behavior
Where are DBH and PNMT found?
DBH is found in the synaptic vesicles of noradrenergic and adrenergic neurons, PNMT is found in the cytocol of adrenergic cells
Which cells secrete adrenaline, where are they found and which neurons are they innervated by?
Chromaffin cells in the adrenal medulla of the adrenal glands (located on top of the kidney) are secreting adrenaline. Chromaffin cells are innervated by cholinergic, sympathetic neurons.
From where in the brain do (nor)adrenergic neurons originate?
The locus coeruleus, which have branches to the entire brain. 90 % NE, 10 % E
What are the functions of histamine?
Sleep regulation, sexual response
How is dopamine involved in Parkinson´s disease?
Loss of dopaminergic neurons in SN projecting to stratium
