Anxiolytics Flashcards
What do fear responses normally comprise of?
Defensive behaviours
Autonomic reflexes
Alertness
Negative emotions
Corticosteroid secretion
Defensive behaviours
Name 3 GABAa agonists
GABA
Muscimol
Ethanol
Name 2 GABAa PAMs
Barbiturate
Benzodiazepine
Describe GABAa receptors
5 subunits
Postsynaptic
Chloride selective
Inhibits CNS function
Cys-loop type ion channel
What is flumazenil?
GABAa NAM
What effects do benzodiazepines have?
Sedation
Hypnosis
Reduced anxiety
Anterograde amnesia
Anti-convulsant
Reduced muscle tone
What subunits in GABAa receptors mediate anxiolytic actions?
α2 subunits
What subunits in GABAa receptors mediate sedative actions?
α1 subunits
How does benzodiazepine increase Cl- influx across GABAa receptors?
Increases frequency of openings
How do barbiturates increase Cl- influx across GABAa receptors?
Increase duration of openings
How can GABAa channel activity be measured?
Cell-attached electrodes. Drugs can be added directly inside the electrode
What property of zolpidem (benzodiazepine) makes it a useful hypnotics?
Short half life
Why can building a tolerance to benzodiazepine be a problem?
Higher doses are required to overcome this
Overdoses can be fatal
Sleepiness and addiction
Misuse
Physical dependence, leading to withdrawal
What is an inverse agonist?
Agonist which reduces constitutive activity when bound
What are benzodiazepines co-administered with?
Anti-depressants (propanolol (beta blocker) blocks sympathetic actions) and SSRIs
