CSGD Quiz 3 2004

1

Which ONE of the following statements about synaptic plasticity is NOT CORRECT?


  The long-term strengthening or weakening of synapses is affected by timing of pre- and post- synaptic activity.

  LTP involves an increase in synaptic strength.

  The NMDA receptor plays an important role in the induction of LTP.

  Synaptic plasticity in the hippocampus has been correlated with spatial memory in rodent models.

  AMPA receptors mediate presynaptic signaling associated with LTP.


Postsynaptic not presynaptic AMPA receptors have been associated with LTP.

2

Which ONE of the following statements regarding drugs of abuse is NOT CORRECT?


  All drugs with abuse potential increase dopamine in the nucleus accumbens.

  The presence of psychological dependence is characterised by intense craving on withdrawal.

  Cocaine causes marked psychological dependence without causing significant physical dependence.

  The active component of cannabis (∆9-THC) is a cannabinoid receptor agonist that causes hallucinations.

  In chronic opioid users, administration of naloxone will prevent a withdrawal response.


Naloxone is an opioid receptor antagonist that will induce a withdrawal response in chronic opioid users (it is used to treat opioid overdose).

3

Which ONE of the following statements about benzodiazepines is NOT CORRECT?


  They may lead to drowsiness and confusion.

  Some undergo hydroxylation to active metabolites.

  They are useful in the treatment of anxiety, and as hypnotics (to induce sleep).

  They all share a similar duration of action.

  They facilitate the opening of GABA activated chloride channels.


D is not correct because one of the marked features of the benzodiazepines that affects how they are used clinically is their varying pharmacokinetic properties. Some of the drugs undergo conversion to long acting metabolites (eg diazepam, converted to nordazepam, with a half-life of 60 h). For some of the drugs, hydroxylation reduces their activity. For the benzodiazepines the other main metabolic process is glucuronidation (a phase II process, which can either follow a phase I reaction such as hydroxylation, or proceed directly from the parent drug eg lorazepam) refer to powerpoint slide from lecture - or Rang Dale & Ritter. Thus the duration of action varies from drug to drug.

A, B, C, and E are all true for the benzodiazepines.

4

Which ONE of the following statements about noradrenergic transmission in the central nervous system is NOT CORRECT?


  Drugs that deplete noradrenaline levels in the brain can cause depression.

  Drugs that block the metabolism of noradrenaline by monoamine oxidase produce dependence.

  Drugs that block the neuronal uptake of noradrenaline can enhance mood.

  L-DOPA is a precursor for noradrenaline that crosses the blood brain barrier.

  Dopamine is a precursor for noradrenaline that cannot cross the blood brain barrier.


Monoamine oxidase inhibitors are effective anti-depressants that have a slow onset of action and do not cause dependence. Cocaine (inhibits noradrenaline uptake) and amphetamine (releases noradrenaline from vesicular stores) are drugs that can cause dependence but this is related to their rapid acute effects on dopaminergic transmission.

5

Which ONE of the following statements about the ageing of various organs in the body is NOT CORRECT?


  With ageing, the renal blood flow is decreased, but medullary flow is unchanged.

  It is possible to improve strength in the elderly by weight training.

  With ageing, there is a reduced ability of the skin to absorb vitamin D.

  There is no gender difference in bone loss in ageing individuals.

  There is no change in haemoglobin levels with age.


As women age they generally lose much more bone than men. The other answers are correct statements.

6

Which ONE of the following clinical features of delirium is NOT CORRECT?


  Lucid periods may be seen.

  Patients are usually oriented appropriately in place and time.

  Hallucinations and delusions are common.

  The onset can be subacute in nature.

  The mortality rate is high.


Patients with delirium are disorientated in time and place. All of the other answers are features seen in patients with delirium.

7

Which ONE of the following statements is NOT CORRECT?


  Individuals with Down Syndrome have an increased risk of certain cardiovascular and gastrointestinal problems.

  The presence of only one X chromosome, in the absence of a second sex chromosome, results in Turner Syndrome.

  Edward Syndrome is caused by trisomy 13.

  Familial adenomatous polyposis is caused by haploinsufficiency of the APC gene.

  Paternal uniparental disomy of chromosome 11p is a cause of Beckwith Wiedemann Syndrome.


Edward syndrome is caused by trisomy 18. The other answers are correct.

8

Which ONE of the following statements regarding early embryo development is CORRECT?


  Neural crest cells are induced by sonic hedgehog.

  Neural crest cells are not involved in the development of the craniofacial skeleton.

  Cyclopia results from a failure of forebrain development.

  The patterns of Hox gene expression are used to define specific regions within the forebrain.

  The cranial vault is derived from pharyngeal arch 1.


All of the other answers are incorrect.

9

Which ONE of the following statements regarding prescribing drugs for an older person is CORRECT?


  It is important that digoxin is prescribed in a dose that ensures the blood level is in the "therapeutic range"

  Female gender is the biggest individual risk factor resulting in an adverse drug reaction.

  Angiotensin converting enzyme inhibitors are as effective in the management of heart failure in patients over the age of 80 years as they are in those under 65 years of age.

  The use of benzodiazepines significantly increases the risk of hip fractures.

  The loading dose of a drug often needs to be increased.


Falls and hip fractures are more common in older patients taking benzodiazepines. A is incorrect: Digoxin does have a low therapeutic index, but its effects are not reliably predictable from serum levels. B is incorrect: Female gender is associated with polypharmacy, but not an increased risk of ADRs. C is incorrect: Decline in associated organ systems will change the response profile of ACE inhibitors in older patients. E is incorrect: The loading dose often needs to be decreased due to decrease drug metabolism.

10

Which ONE of the following agents is NOT a potential teratogen?


  Folic acid.

  Valproic acid.

  Methotrexate.

  Alcohol.

  Nicotine.


All except folic acid are potential teratogens. In fact, folic acid is used prophylactically to reduce the incidence of neural tube defects in the fetus.

Valproic acid: 'Category D' - related to sodium valproate (anti-convulsant, mood stabiliser), is a known folate antagonist.
Alcohol: 'Category X' - fetal alcohol syndrome.
Methotrexate: Category D - inhibits metabolism of folic acid.
Nicotine is not teratogenic, although it is associated with underdevelopment.