chapter 3 (how drugs work in body and mind)

Question 1

4 routes of drug administration

Answer 1

1. oral administration
2. injection
3. inhalation
4. absorption through skin/membranes

Question 2

what is the safest way to administer a drug?

Answer 2

orally

Question 3

what characteristic is necessary of drugs to pass through the fat membrane between the gastrointestinal tract and blood capillaries?

Answer 3

substances must be lipid-soluble (soluble in fats)

Question 4

intravenous (i.v.)

Answer 4

into a vein. as injection, takes approx. 15 seconds.

Question 5

intramuscular (i.m.)

Answer 5

into a muscle. as injection, usually into large muscle like upper arm, thigh, buttock. absorbed into bloodstream through capillaries serving muscle. takes longer than i.v.

Question 5

subcutaneous (s.c./sub-Q)

Answer 5

underneath the skin. as injection, slowest method because of less abundant blood supply. only small amounts.

Question 5

intranasal

Answer 5

into the nasal cavity.

Question 5

inhalation

Answer 5

breathing in particles of the drug through smoke or vapours. faster than i.v., takes 5-8 seconds.

Question 5

sublingually

Answer 5

applied under the tongue. absorbed through membranes of mouth.

Question 6

transdermal patch

Answer 6

device attached to the skin that slowly delivers the drug through skin absorption.

Question 7

biotransformation

Answer 7

process of changing the molecular structure of a drug into forms that make it easier for the body to excrete it. how urinary excretion begins, mostly through enzymes in liver.

Question 8

metabolite

Answer 8

by-product resulting from biotransformation process. structurally modified forms of original drug.

Question 9

enzyme induction

Answer 9

repeated drug taking results in greater production of liver enzymes that metabolize that drug and similar ones.

Question 10

enzyme inhibition

Answer 10

repeated drug taking stops the action of specific liver enzymes and metabolism of drug slows down.

Question 11

drug competition

Answer 11

drugs taken in combination occupy all available liver enzymes leaving excess drugs nonmetabolized & resulting in toxic levels.

Question 12

elimination half-life

Answer 12

length of time it takes for a drug to be reduced to 50% of its equilibrium level in bloodstream. (original concentration level.)

Question 13

latency period

Answer 13

an interval of time during which blood levels of a drug are not yet sufficient for a drug effect to be observed.

Question 14

cross-tolerance

Answer 14

phenomenon in which the tolerance that results from the chronic use of one drug induces a tolerance effect with regard to a second drug that has not been used before. (ex: alochol, barbiturates, benzos.)

Question 15

cross-dependence

Answer 15

phenomenon in which one drug can be used to reduce the withdrawal symptoms following the discontinuance of of another drug.

Question 16

central nervous sytem (cns)

Answer 16

portion of ns consisting of brain and spinal cord.

Question 17

peripheral nervous system (pns)

Answer 17

portion of ns consisting of nerves and nerve fibers that carry info to cns and outward to muscles and glands. breaks down into somatic and autonomic ns.

Question 18

sympathetic nervous system

Answer 18

portion of autonomic ns that controls bodily changes that deal with stressful/emergency situations.

Question 19

parasympathetic nervous system

Answer 19

portion of autonomic ns that controls bodily changes that lead to increased nurturance, rest, and maintenance.

Question 20

neuron

Answer 20

specialized cell in the nervous system that receives and transmits info. where psychoactive drugs do their work.

Question 21

action potential

Answer 21

electrical message generated at the cell body that moves down the axon and causes release of nt.

Question 21

cerebral cortex (neocortex)

Answer 21

portion of forebrain responsible for higher level information processing.

Question 22

presynaptic terminals

Answer 22

at end of axon where nt is released.

Question 23

resting membrane potential

Answer 23

difference in electrical charge between the inside and outside of neuron (~ -70 mV) when neuron is not being stimulated or inhibited.

Question 24

synapse

Answer 24

juncture between neurons. consists of presynaptic terminal, intervening gap, and postsynaptic terminal containing receptor sites on the receiving neuron.

Question 25

neurotransmitter

Answer 25

chemical substance that a neuron uses to communicate info at synapse.

Question 26

reuptake

Answer 26

process by which a nt is transported from synapse back up into presynaptic terminal.

Question 27

glutamate

Answer 27

most common excitatory nt. glutamate receptors associated with actions of PSP and ketamine and feelings of drug craving.

Question 28

gamma aminobutyric acid (GABA)

Answer 28

most common inhibitory nt. antianxiety and anticonvulsant drugs tend to facilitate activity of GABA receptors in brain.

Question 29

ionotropic receptor (ligand-gated ion channel)

Answer 29

cell membrane receptor-ion channel complex that allows specific ions to pass when receptor is activated. effects are fast.

Question 30

metabotropic receptor

Answer 30

cell membrane receptor that is linked to a G protein. activation results in production of a second messenger that can have variety of intracellular functions. slow changes.

Question 31

agonist

Answer 31

substance that binds to a receptor site, like the endogenous neurotransmitter, and produces the same response.

Question 32

antagonist

Answer 32

substance that binds to a receptor site and decreases or eliminates the effectiveness of the endogenous neurotransmitter,

Question 33

acetylcholine

Answer 33

neurotransmitter active in the parasympathetic autonomic ns, cerebral cortex, and peripheral somatic nerves.

Question 34

norepinephrine (noradrenaline)

Answer 34

neurotransmitter active in sympathetic autonomic ns and in many regions of the brain.

Question 35

dopamine

Answer 35

neurotransmitter in brain whose activity is related to motor control, learning/memory/emotionality, and cravings. binds to metabotropic dopamine receptors.

Question 36

serotonin (5-hydroxytrytophan/5-HT)

Answer 36

neurotransmitter in the brain whose activity is related to emotionality and sleep patterns.

Question 37

endorphins

Answer 37

class of chemical substances produced in brain and elsewhere in body that act on same opiate receptors as morphine, heroin, and codeine.

Question 38

endocannabinoids

Answer 38

brain-produced chemicals that mimic effects of active ingredient in marijuana and other cannabis products.

Question 39

blood-brain barrier

Answer 39

specialized separation between the bloodstream and cns that keeps toxins and large molecules out of the brain.

Question 40

nucleus accumbens

Answer 40

region in limbic system of brain responsible for the rewarding effects of many drugs of abuse. related to release of dopamine in this area.

Question 41

placebo

Answer 41

any inert substance that produces a psychological or physiological reaction.

Question 42

double-blind

Answer 42

procedure in drug research in which neither the individual administering a chemical substance nor the individual receiving it knows whether the substance is the drug being evaluated or an active placebo.

Question 43

metabolic (dispositional) tolerance

Answer 43

over repeated administrations, drug facilitates the processes that the produce the drug’s biotransformations in liver.

Question 44

cellular (pharmacodynamic) tolerance

Answer 44

receptors stimulated by drug over time become less sensitive or removed from synapse altogether (receptor down-regulation) or repeated blocking of receptors may increase number of receptors or amount of neurotransmitter released (receptor up-regulation.)