Regulating Transmitter Levels: Dopamine Flashcards
What neurotransmitters are involved in the extrapyramidal motor system?
dopamine, acetylcholine, GABA
What are the motor signs and symptoms of Parkinson’s?
tremor, rigidity of limbs, bradykinesia, impairment of postural reflexes, no blinking, monotonous speech, decreased manual dexterity
What are the non-motor signs and symptoms of Parkinson’s?
cognitive deficiencies, depression, raised anxiety, olfactory deficiencies, sleep disturbances, fatigue, pain, bowel and bladder problems, sexual dysfunction
What neurodegeneration happens in Parkinson’s disease?
dopaminergic nerves in the substantia nigra degenerate
What are the 4 techniques used to aim to restore the dopamine deficiency in Parkinson’s?
increase synthesis, increase release, dopamine receptor agonist, reduce dopaminergic metabolism
What technique is used to aim to restore the dopaminergic/cholinergic imbalance in the striatum in Parkinson’s?
cholinergic antagonists
How is dopamine synthesised?
tyrosine is converted to L-DOPA by tyrosine hydroxylase, L-DOPA is converted to dopamine by dopadecarboxylase
How is dopamine metabolised?
by MAO and COMT
What is the main pharmacological treatment for Parkinson’s?
levodopa with carbidopa or benserazide (a DDC inhibitor for the periphery)
Why does effectiveness of levodopa decline with time?
because the treatment increases the degeneration of the neurons due to oxidative stress
What are the adverse effects of levodopa?
anorexia, nausea, vomiting, tachycardia, ventricular dysrhythmias, orthostatic hypotension, pupil dilation, visual and auditory hallucinations, dyskinesia, depression, anxiety
What dopamine agonists are used in the treatment of Parkinson’s?
bromocriptine, cabergoline, pergolide
What drug is used to block metabolism of dopamine by COMT?
entacapone
What drug is used to block metabolism of dopamine by MAO?
selegeline
Which muscarinic receptor antagonists are used in the treatment of Parkinson’s?
bezhexol, benztropine, biperiden, orphenadrine
