Lecture 12 - anxiolytics and hypnotics

Question 1

what are the drugs used to treat anxiety called?

Answer 1

anxiolytics

Question 2

what are the drugs used to treat sleep disorders called?

Answer 2

hypnotics

Question 3

what is panic disorder?

Answer 3

sudden attacks of overwhelming fear. this causes sweating, tachycardia, chest pains, trembling and choking

Question 4

what is OCD?

Answer 4

compulsive ritualistic behaviour driven by irrational anxiety

Question 5

drugs that are anxiolytic/ hypnotic agents

Answer 5

benzodiazepines and barbiturates

Question 6

why are benzodiazepines less used?

Answer 6

• they have unwanted side effects like amnesia

Question 7

what is the role of propranolol?

Answer 7

acts as a beta antagonist to block somatic symptoms

Question 8

elevated plus maze cross model for anxiety

Answer 8

• one side of the cross has a barrier and on other side there is no barrier.
• place rodent in the centre but is afraid to go to the open part of the cross.
• with drugs, the rodent has no preference

Question 9

Light/dark box model for anxiety

Answer 9

• one side is open to daylight and other side can be dark. rodent normally goes to the dark side. with drugs, rodent has no fear of going to the light.

Question 10

what is a conflict test?

Answer 10

associates treat with a mild shock if rodent goes for the treat. with anxiolytic, rodent ignores shock and goes for treat.

Question 11

what are benzodiazepines target?

Answer 11

GABAa receptors

Question 12

structure of a GABAa receptor

Answer 12

made up of 5 subunits, 2 alpha, 2 beta and 1 gamma. 2 binding sites for GABAa which need to be occupied to function.

Question 13

where is the binding site for GABA?

Answer 13

between the alpha and beta subunit

Question 14

where is the benzodiazepine binding site?

Answer 14

between alpha and gamma subunit

Question 15

what type of neurotransmission is mediated by GABAa receptors?

Answer 15

inhibitory neurotransmission as membrane potential gets more negative as its chloride selective

Question 16

what is the orthosteric site?

Answer 16

where agonist that opens the channel binds (GABA) and muscimol. Competitive antagonist is bicuculline and picrotoxin is non competitive

Question 17

what is the allosteric site?

Answer 17

where agonist can bind like benzodiazepines. does not activate receptor but modifies the behaviour of receptor

Question 18

what are the subunit sensitivities for benzodiazepines?

Answer 18

alpha 1,2,3 and 5 and a gamma subunit

Question 19

physiological effect of activating GABAa receptor?

Answer 19

-decreased responsiveness so less sensitive. as concentration is increases, the hypnosis is increased so makes you more tired.

Question 20

subunit that has anti-anxiety effects?

Answer 20

alpha 2 subunits

Question 21

subunit that has hypnotic effect

Answer 21

alpha 1 subunit

Question 22

characteristics of benzodiazepines?

Answer 22

• increases response of a neuron to GABA
• positive allosteric regulators of GABAa receptors
• causes channel to be open more often when orthosteric site is also occupied

Question 23

what does the occupation of allosteric site cause?

Answer 23

alters affinity of orthosteric site for agonist and increases affinity so GABA stays in channel which pushes reaction to activation opening

Question 24

role of PAM (positive allosteric modulators)

Answer 24

stabilises receptors in state with increased affinity for GABA to cause leftwards shift in concentraion response curve

Question 25

role of NAM (negative allosteric modulators)

Answer 25

stabilises receptor by reducing affinity of receptor for agonist of orthosteric site. these drugs help with remembering things.

Question 26

effects of benzodiazepine agonists?

Answer 26

• can lead to development of tolerance so drug is less effective
• 2-3 weeks on diazepam can have physical dependence so withdrawal syndrome
• alcohol with these drugs can be fatal
• barbiturates at high dose increase CNS depression to death

Question 27

what are the drugs used to treat anxiety?

Answer 27

• benzodiazepines (now limited) for acute anxiety
• propranolol for somatic mechanisms
• SSRIs used for generalise anxiety
• Buspirone (serotonin partial agonist) not good for panic disorders.

Question 28

drugs used to treat insomnia

Answer 28

• short-acting benzodiazepines (lorazepam)
• melatonin receptor agonists
• orexin receptor antagonists
• sleep aids (promethazine)