Dopamine System - 30 Flashcards
What is psychosis?
Disorganized or irrational behavior
What types of symptoms are there of schizophrenia?
Cognitive dysfunction, positive symptoms, and negative symptoms
When does Schizophrenia arise?
Typically late teens-early 20s
Other than genetics, what can cause schizophrenia?
Idiopathic, metabolic, drug induced (PCP, meth/amphetamine)
What is the Dopamine hypothesis?
Schizophrenia is caused by overactive dopamine system; because drugs that block D2 dopamine receptors reduce symptoms
Where is the imbalance of dopamine in regards to schizophrenia?
Increased limbic : decreased prefrontal cortex
What evidence is there to support the dopamine hypothesis?
Blocking DA receptors improves symptoms; high doses of amphetamine produce similar paranoid psychosis symptoms; greater dopamine release in those w/ psychosis; inhibiting dopamine reduces symptoms of schizophrenia
What will be seen in a brain 5 years after the onset of schizophrenia?
Loss of grey matter
What brain regions are involved in schizophrenia (mainly)?
See P-Coats
Caudate, Prefrontal Cortex, Occipital cortex, Amygdala, Thalamus, Striatum
Why might patients with Schizophrenia have impaired oral hygiene?
Inability to think clearly/plan
What are some of the dental implications of Schizophrenia?
Heavy smokers/coffee drinkers; impaired gag reflex; xerostomia; drug interactions
What is the strangest treatment for Schizophrenia?
Electroconvulsive Shock Therapy (still used today)
What symptoms of schizophrenia are best treated by anti-psychotics?
Positive symptoms (there’s a snake in my boot….. no there’s not)
What mechanism do anti-psychotics work by?
They interfere with Dopamine transmission (mostly block receptors)
There is a strong relationship between _____________________ and ________________. (Treating schizophrenia)
Potency at the D2 DA receptor : effective dose
Better binding = lower dose needed
What is the most commonly used First Generation Anti-psychotic drug?
Haloperidol
What are the most common Second Generation Anti-psychotics?
Risperidone, Olanzapine, Aripiprazole
What is a key pharmacological property of antipsychotic drugs?
High therapeutic index
What other receptors (other than DA) do anti-psychotics work on that cause unwanted side effects?
Alpha-adrenergic, muscarinic Ach, histamine (activates), serotonin
What are some unwanted side effects of antipsychotics (physiologically)?
Increased prolactin (on target); Poikilothermic effects; Antiemetic effects
Characteristically, how are antipsychotics absorbed?
Erratically (unpredictably)
What is the half life of antipsychotics?
6-40hrs
How do antipsychotics react with the BBB?
Pass through easily (very lipophilic)
S1/S2 - Patients who take antipsychotics for prolonged periods will build tolerance to the sedative effects. They will also build a tolerance to the prolactin secretion.
Statement 1 is true. Statement 2 is false
T/F Antipsychotics are highly addictive
F
What will happen if a patient stops taking their antipsychotics abruptly?
RELAPSE
What are some unwanted side effects of antipsychotics (will ask why they happen)?
Sedation/CNS depression; Antimuscarinic; Antiadrenergic; Extrapyramidal (neurological)
What causes the Sedation/CNS effects?
Activation of histamine receptors
What are antimuscarinic effects?
Dry mouth/drowsiness
Why are there neurological side effects?
Over-activation of dopamine receptors (receptors that aren’t blocked are now over-activated)
What happens if you give too much Haloperidol?
Parkinsonian syndrome
What are some of the neurological side effects?
Tardive dyskinesias (tics around the mouth)
T/F Second generation anti-psychotics have much less side effects
T
What percentage of D2Rs must be blocked for a therapeutic effect? Pyramidal effect?
60% : 80%
What are the “affective disorders”?
Depression and Bipolar disorder
What is the prevalence of depression? Onset?
17% : 11 yrs old
What is required for a diagnosis of major depression?
> (or equal) 5/9 symptoms
Why are those with depression prone to periodontitis/tooth decay?
Lower immune response; clenching; neglect oral hygiene; more lactobacillus; dry mouth (side effect)
What is the goal of antidepressants?
To increase serotonin transmission
What are the tricyclics antidepressant drugs?
Amitriptyline; Imipramine
What is an example of an SSRI?
Fluoxetine (Prozac)
How do Tricyclics antidepressants work?
They block the serotonin transporter
What other issues can trycyclic antidepressants treat?
Trigeminal neuralgia and facial pain
What does SSRI stand for? What’s good about them?
Selective Serotonin Reuptake Inhibitor. They only work on Serotonin receptors so no muscarinic/histaminic/adrenergic side effects
What effect does SSRIs have on Benzos?
It inhibits P450s (prolongs effects)
