Pharmacology in the CNS Flashcards
What is the function of the blood brain barrier?
Maintain constant environment
Protect brain from foreign substances
Protect brain from peripheral transmitters
Why is drug entry to the CNS severely restricted?
Blood brain barrier (BBB)
Name a structure that lies functionally outwith the BBB.
Area postrema - vomit reflex
Name some problems associated with disease of the blood brain barrier.
Hypertension, infection, trauma, substances which can enter the CNS and cause toxicity.
Name some routes of drug administration into the CNS.
Enteral - i.e. lipophylic drugs
Perenteral (not enterally)
i.e. intrathecal - meningitis antibiotics, opiate analgesics, regional anaesthesia (epidural)
Name some different approaches to aid entry of drugs into the CNS.
Prodrugs i.e. L-DOPA
Carrier molecules
Transient BBB disruption (e.g. mannitol)
How does a partial agonist work?
partially activates a receptor, producing a functional response in the cell.
Define general anaesthetic agents and list some examples.
Drugs used to produce surgical anaesthesia.
Halothane, isoflurane (inhalational)
Propofol (intravenous)
Define anxiolytics and sedatives.
Drugs that cause sleep and reduce anxiety. AKA hypnotics, minor tranquilisers.
Barbiturates
Benzodiazepines (diazepam)
Define antischizophenia (antipsychotic) drugs and list some examples.
Drugs that are effective in relieving the symptoms of schizophrenic illness AKA neuroleptics, major tranquilisers.
Typical - chlorpromazine, haloperidol.
Atypical - clozapine, olanzapine.
Give some examples of antidepressant drugs.
monoamine oxidase inhibitors (phenelzine)
tricyclic antidepressants (imipramine)
SSRIs (fluoxitine)
What is the normal therapeutic onset of antidepressant drugs?
2-4 weeks.
What are analgesics? Name some.
drugs used clinically for controlling pain.
opiates (e.g. morphine, buprenorphine)
baclofen (gabba B receptor agonists)
NSAIDs (ibuprofen, aspirin)
What are psychomotor stimulants? Name some.
Drugs that cause wakefulness and europhia.
Cocaine, amphetamine
methylphenidate (ritalin)
caffeine
What are psychotomimetic drugs? Name some.
Drugs that cause disturbances of perception and of behaviour , that cannot be simply characterised as having sedative or stimulant effects.
LSD, ketamine.
What are cognition enhancers? Name some.
Drugs that improve memory and cognition performance.
Galantamine, donepezil (AChE inhibitors - Alzheimer’s disease)
Gabapentin is a drug specific for what disease?
Epilepsy
L-DOPA is a drug for what specific disease?
Parkinson’s
Lithium is a drug used to treat what disorder?
Bipolar disorder.
Why does most CNS drug treatment need improving?
Delayed therapeutic onset
Inadequate therapeutic efficacy
Side effects
Where is dopamine produced in the brain?
Hypothalamus, substantia nigra.
Degeneration of the nigrostriatal pathway (required for fine motor control) occurs in what disease?
Parkinson’s disease.
Name 3 of the major characteristics of Parkinson’s disease.
Tremor, hypokinesia, rigidity.
What are some of the causes of parkinson’s disease?
Aging Genetic factors (synuclein, parkin and other risk genes) Environmental factors (toxins, herbicides, pesticides)
Describe three therapies which aim to treat Parkinson’s disease.
- Replace dopamine (L-DOPA)
- Mimic dopamine action (D2/3 agonists - bromocriptine)
- Reduce dopamine breakdown (MAOIs - selegiline)
What are some side-effects of dopamine agonists?
- Hallucinations
2. Pathological gambling/shopping
List some of the symptoms of schizophrenia.
Hallucinations, delusions, sustained depression, anhedonia (inability to feel pleasure), avolition (lack of drive), impaired attention.
How does schizophrenia treatment work?
Reduce dopaminergic signalling at D2 dopamine receptors (D2 agonists).
What are some of the side effects of D2 agonists?
akinesia, prolactin hypersecretion, postural hypotension, sedation, dry mouth, weight gain.
Dopamine travels to the anterior pituitary gland where it binds to prolactin secreting cells. How does it get there?
It is secreted into the portal blood vessels.
What effect does dopamine have on prolactin secretion?
dopamine decreases prolactin secretion.
Describe the tuberohypophyseal system.
Group of short dopamine neurons that projects from the arcurate nucleus in the hypothalamus to the median eminence.
What effect does dopamine have on growth hormone?
Growth hormone is increased by dopamine.
