Psychopharmacology Flashcards
Describe how neurotransmission works ?
-The presynaptic neuron synthesizes, transports and stores the neurotransmitter
-Synthesis takes place in cell body / soma which contains the essential protein synthesis machinery.
-From here axonal transport occurs, and the neurotransmitter reaches the synaptic terminal.
-Before its eventual release, the neurotransmitter is stored within the synaptic vesicle.
- The release takes place through the process of membrane fusion and exocytosis.
List 3 ways in which cessation of a neurotransmitter takes place.
1.Reuptake back to presynaptic neuron via special transporters (e.g. monoamine transporters)
2.Enzymatic breakdown at the cleft (e.g. via Catechol-O-methyltransferase/MAO-A enzyme)
3.Removed by glia or plasma circulation (e.g. glutamate shuttle)
What are the 2 types of glial cells and where are they found?
Glial cells –Schwann (CNS) and Oligondendrocytes (PNS)
What are the two ways of classifying neurotransmitters?
1.As either inhibitory and excitatory
2. As either monoamines, peptides and amino acids
Give 2 examples of inhibitory neurotransmitters?
1.Dopamine
2.GABA
Give 5 examples of excitatory neurotransmitters
1.Serotonin
2.Glutamate
3.Adrenaline
4.Noradrenaline
5.Dopamine
List 3 examples of amino acids?
-Glycine
-Glutamate
-GABA
List 6 examples of monoamine neurotransmitters ?
1.Serotonin
2.Dopamone
3.Noradrenaline
4.Adrenaline
5.Acetylcholine
6.Histamine
List 6 examples of peptides?
1.Ghrelin
2.Leptin
3.Neuropeptide Y
4.Neurotensin
5.Cholecystokinin
6.Endorphins
List the 4 Dopamine pathways together with their origin and destination?
1.Nigrostriatal pathway
Substantia Nigra to the striatum and amygdala via medial forebrain bundle.
2.Mesolimbic pathway
Ventral tegmental are to the Nucleus accumbens and hippocampus via medial forebrain bundle
3.Mesocortical Pathway
VTA - prefrontal regions and cingulate cortex via the medial forebrain bundle
4.Tuberoinfundibular pathway from hypothalamus to pituitary via portal vessels
What is the effect of dopamine blockade to the 4 dopamine pathways ?
Nigrostriatal pathway cause extrapyramidal side effects
Mesolimbic Pathway -Causes the desirable antipsychotic effect by controlling positive psychotic symptoms
Mesocortical pathway - DA blockade or low levels of dopamine will result in negative symptoms (neuroleptic induced deficit syndrome)
Tuberoinfundibular pathway- dopamine blockade will result in increase in prolactin levels.
List 5negative symptoms and describe them?
1.Alogia -reduced amount of spontaneous speech
2.Anhedonia -inability to experience pleasure from activities that were once enjoyable
3. Amotivation/Avolition-lack of motivation to engage in goal directed behavior thus making it difficult to initiate or complete tasks.
4.Asociality- lack of motivation to engage in social interactions
5.Affective flattening-reduced range of emotional expression or showing little emotion.
List 6 ways in which drugs increases or decrease the effect of the neurotransmitter?
1.Being a precursor for the neurotransmitter
2.Stopping production
3.Stopping storage
4.Increasing/reducing release
5.Mimicking/blocking at the receptor
6.Increasing/reducing reuptake or breakdown
What are the two types of antipsychotics?
1st generation-typical
2nd generation-atypical
What is the MOA of 1st generation antipsychotics?
They mainly block D2 receptors in the mesolimbic pathway
But also result in the blockade of adrenergic, histamine and muscarinic receptors.
Give 3 examples of 1st generation antipsychotics.
Haloperidol(High potency)
Fluphenazine
Chlorpromazine(Low potency)
List 4 extrapyramidal effects? And define them
1.Dystonia -sustained muscle contraction
2.Parkisonism
3.Akathisia - disorder characterized by the uncontrolled need to move./internal sense of restlessness characterized by pacing, taping
4.Tardive dyskinesia-repetitive uncontrolled movement of the lips, tongue, trunk and extremities
What are the types of dystonia? Describe them?
Oculogyric crisis -involuntary upward deviation of both eyes due to spasms and increased tone in the extraocular muscles.
Torticollis -condition in which the neck muscles contract, causing the head to twist to one side.
Trismus-Locked jaw
Orthotonus- tetanic spasm characterized by rigid straightness of the body.
What are the signs and symptoms of Parkinsonism (5) ?
Shuffling gait, resting tremors, dyskinesia, cogwheel rigidity, bradykinesia
What is the treatment for each of the extrapyramidal symptoms?
1.Tardive Dyskinesia-Discontinue antipsychotic and +/- Clozapine
2. Parkinsonism and Dystonia -Anticholinergic
3.Akathisia- Beta blocker
What are the antiadrenergic effects , antihistaminic effects and antimuscarinic of antipsychotics?
Antiadrenergic effects
Sedation
Postural hypotension
Inhibition of ejaculation
Antihistaminic effects
Sedation
Weight gain
Antimuscarinic effects
Anihidrosis
Blurry vision
Constipation
Urinary retention
Dry mouth and drowsiness
What is the relationship between dopamine and Ach and how does this affect treatment?
-Dopamine and acetylcholine have a reciprocal relationship with each other in the nigrostriatal pathway
-Implication: high potency antipsychotics (haloperidol) have less anticholinergic effects but high EPSE while low potency antipsychotics (chlorpromazine) are more sedating but less EPSE
What is the difference between 1st gen and 2nd gen antipsychotics?
-2nd gen antipsychotic block 5HT2A receptors thus increasing dopamine release and as a result reducing EPS
-2nd gen have a greater propensity for metabolic side effects
What is resistant schizophrenia?
Trial of at least 2 different antipsychotics at their maximum effective doses for a period of at least 6 weeks of which one antipsychotic has to be a second generation antipsychotic.
