psychopharmacology - part 2

Question 1

different types of drug action

Answer 1

agonism

antagonism

allosteric modulation

Question 2

agonism - direct and indirect

Answer 2

direct - mimics the effect of a neurotransmitter by binding the postsynaptic receptors in a similar way and producing a similar response in the postsynaptic neuron

indirect - enhances the action of a natural neurotransmitter

Question 3

agonism - full, partial, inverse

Answer 3

full - generate a maximal response at a receptor

partial - generate a fraction of the possible response at a receptor

inverse - cause a decrease in signalling at a receptor

Question 4

agonism

Answer 4

enhances natural action

Question 5

antagonism - direct and indirect

Answer 5

direct - binds to receptor but has no physiological effect at receptor

indirect - involves inactivation of the enzymes that synthesises neurotransmitters pr inhibiton of release

Question 6

antagonism - reversible and irreversible

Answer 6

reversibe competitive - competes for binding site (blocks)

irreversible competitve - form a stable bond with an agonists binding site

Question 7

allosteric modulation

Answer 7

a substance that indirectly influences neurotransmission by acting at a site distinct from the primary binding site to modify receptor structure

many increase/decrease likelihood an agonist will bind
enhance/reduce effects of agonist

Question 8

drug efficiency

Answer 8

= the extent to which a drug activates a receptor

dose response curve –> smallest dose w/ same effect = more efficient

Question 9

drug efficiency - antagonist

Answer 9

have no efficiency because they dont induce a response

Question 10

drug efficiency - full agonist

Answer 10

induce maximal response

Question 11

drug efficiency - full inverse agonist

Answer 11

induce maximal response in the opposite direction

Question 12

drug efficiency - partial agonist

Answer 12

depend upon the background level of neurotransmitter activity
- useful when stabilisation is needed (eg, bring back to normal levels)

Question 13

do drugs have selective responses

Answer 13

even if a drug is selective for a particular receptor it is likely to have more than one effect on behaviour

Question 14

the therapeutic index

Answer 14

= the relationship between toxic and therapeutic dose

determines the safety of the drug

large therapeutic index preferred

Question 15

the therapeutic index
how to calculate

Answer 15

calculated as the dose of the drug that elicts a lethal response in 50% of samples (LD50) divided by the dose that elicits a desired response in 50% of a sample (ED50)

LD50 / ED50

if above 100 a drug is safe