Drugs Brain and Mind - Chapter 1

studied byStudied by 0 people
0.0(0)
learn
LearnA personalized and smart learning plan
exam
Practice TestTake a test on your terms and definitions
spaced repetition
Spaced RepetitionScientifically backed study method
heart puzzle
Matching GameHow quick can you match all your cards?
flashcards
FlashcardsStudy terms and definitions

1 / 74

encourage image

There's no tags or description

Looks like no one added any tags here yet for you.

75 Terms

1

drug action

molecular changes produced by a drug when it binds to a target site

New cards
2

drug effects

effects of the molecular changes in pathway function on physiological and psychological processes (e.g. behavior)?

New cards
3

therapeutic effects

drug-receptor interaction that produces the desired changes (physical or behavioral)

New cards
4

side effects

all other effects of a drug-receptor interaction that are not the desired change

New cards
5

specific effects

based on physical and biochemical interactions of a drug with a target site on living tissue

New cards
6

nonspecific effects

effects not based on drug-receptor interaction (e.g. placebo effect)

New cards
7

placebo effect

belief in a drug may produce real physiological effects despite the lack of chemical activity

New cards
8

bioavailability

the concentration of drug present in blood that is free to bind to specific target sites

New cards
9

factors that contribute to bioavailability

R - route of administration

A - absorption and distribution

B - binding

I - inactivation

E - excretion

New cards
10

route of administration

influences how much drug reaches its target and how quickly the effect occurs

New cards
11

absorption

movement of the drug from the site of administration to the blood circulation (must cross semi-impermeable membranes before reaching system circulation unless given intravenously)

New cards
12

oral (PO) administration

drug must pass through wall of stomach or intestine - first pass metabolism

food slows movement of drugs into the intestine

New cards
13

first pass metabolism (pre-systemic metabolism)

potentially harmful chemicals pass via the portal vein (from GI tract) to the liver » chemically altered, reduces bioavailability of the drug

New cards
14

inhalation administration

drug passes directly from lungs into blood through heart to brain, rapid absorption through pulmonary capillaries

rapid effect in brain - within seconds

New cards
15

intravenous (IV) administration

drug passes into heart, then lungs, back through heart, and then to brain

most rapid and accurate method of drug administration

New cards
16

intranasal administration

local (nasal passages) and system effect - moves across single epithelial layer into the blood

bypasses the blood brain barrier (BBB) and has direct access to the CSF, direct transport of drugs to brain via olfactory nerve pathways

New cards
17

gene therapy

application of DNA that encodes a specific protein

New cards
18

lipid-soluble drugs

pass through cell membranes by passive diffusion moving down concentration gradients, can easily enter brain tissue

most drugs are not lipid-soluble

New cards
19

weak acid drugs

more readily ionized in basic environments, less ionized in acidic environments

New cards
20

weak base drugs

more readily ionized in acidic environments, less ionized in basic environments

New cards
21

acid/base drugs

non-lipid soluble drugs

highly ionized drugs are poorly absorbed from the GI tract and cannot be given by PO (orally)

New cards
22

small intestine

most drug absorption occurs at this site

much more surface are and slower movement of material, more permeable

New cards
23

methods of non-lipid soluble transport

facilitated diffusion and active transport

fenestration, intercellular clefts, pinocytotic vesicles

New cards
24

blood brain barrier

separation between brain capillaries and brain/CSF, semi-permeable

protect, shields, and maintains

unisolated areas: area postrema in the medulla, median eminence of the hypothalamus

New cards
25

area postrema

chemical trigger zone in the medulla, senses toxins, induces vomiting reflex

not protected by the BBB

New cards
26

median eminence

hypothalamus, release of hormones induced in the stress response

not protected by the BBB

New cards
27

blood capillary barriers

tighter cellular junctions

protective end feet of astrocytes

no intercellular clefts or fenestration, only carrier-mediated transport

New cards
28

placental barrier

separation of blood circulation between mother and fetus at the placenta

New cards
29

teratogens

agents that induce developmental abnormalities

New cards
30

thalidomide

sleep aid marketed for morning sickness

10,000 cases worldwide documented of abnormal limb development

New cards
31

drug depots

drug binding at inactive sites where no biological effect is initiated

plasma proteins, muscle, and fat

New cards
32

depot binding

affects magnitude and duration of drug action:

  • reduces concentration of drug at sites of action

  • delays effects

  • basis for drug testing

  • individual variability in drug response

  • can lead to termination of action

  • nonselective

  • similar drugs can compete for depot » overdose

New cards
33

drug depot termination

rapid redistribution of drug away form the brain into fatty tissue, leads to sequestration in fatty tissue

New cards
34

biotransformation (metabolism)

process by which drugs are eliminated and metabolites are excreted

New cards
35

first-order kinetics

most drug metabolism

constant fraction of drug eliminated per time unit

concentration-dependent

if drug metabolic sites are NOT saturated by the drug!

New cards
36

plasma half-life (T1/2)

amount of time required for removal of 50% of the drug from the blood plasma - an example of first order kinetics

New cards
37

steady state

absorption/distribution = metabolism/excretion

New cards
38

therapeutic goal

maintain concentration of a drug in blood plasma at a constant level

New cards
39

zero order kinetics

molecules are cleared at a constant rate regardless of concentration

when drug levels are high and routes of metabolism are saturated

rate is concentration independent

New cards
40

type I biotransformation

phase I — CYP 450 enzymes

non-synthetic

could produce a metabolite that is more active than the drug

New cards
41

type II biotransformation

phase II — non-CYP enzymes

synthetic

New cards
42

liver biotransformation

goal: produce inactive metabolites that are water soluble (i.e. ionized)

metabolites formed in the liver are returned to systemic circulation

New cards
43

microsomal enzymes

liver enzymes that metabolize psychoactive drugs

lack specificity - six are responsible for 90% of all oxidizing psychoactive drugs

Phase I reactions

New cards
44

enzyme induction

repeated use of a drug increases number of enzyme molecules » speeds biotransformation

mechanism of drug tolerance and cross tolerance

New cards
45

enzyme inhibition

drug may inhibit an enzyme and reduce metabolism of other drugs

example: monoamine oxidase inhibitor (MAO), major class of antidepressants

New cards
46

drug competition for an enzyme

elevated levels of one drug reduces metabolism of the second, causing potentially toxic levels

New cards
47

urine excretion

most important route for drug elimination

kidneys filter material from blood into urine » excretion of water-soluble (ionized) substances

water and electrolytes reabsorbed into blood circulation; can increase the reabsorption of drugs dependent on pH

New cards
48

pharmacodynamics

what drugs do to the body

New cards
49

partial agonist

drugs that produce a lower response at full receptor occupancy than full agonists

not due to increased affinity for binding

New cards
50

inverse agonist

action that is opposite to that produced by an agonist

New cards
51

indirect agonists

enhances the release or action of an endogenous neurotransmitter but has no specific agonist activity at the NT receptor (e.g. cocaine, amphetamine, MDMA)

New cards
52

receptor up-regulation

number of receptors increases in response to absence of ligands or chronic antagonism

New cards
53

receptor down-regulation

number of receptors is reduced due to chronic activation

New cards
54

threshold dose

smallest dose that produces a measurable effect

New cards
55

efficacy (Emax)

maximum response achieved by a drug

assumes all receptors are occupied (saturated)

New cards
56

ED50 (50% effective dose)

dose that produces half maximal effect (whole animal) OR

dose at which 50% of the population responds (population)

New cards
57

TD50 (50% toxic dose)

dose at which 50% of the population experiences a toxic effect

New cards
58

therapeutic index (TI)

TD50/ED50

higher is better; high TD50 » larger quantity required for toxicity

New cards
59

potency

absolute amount of drug required to produce a specific effect

New cards
60

dose-response curves

semi-log scale: characteristic S shape

linear portion of curves are parallel » work through the same mechanism

New cards
61

affinity

tenacity with which a drug binds to its receptor

rates of dissociation and association are compared to get an estimate of receptor affinity: dissociation constant (Kd)

  • high affinity: low Kd

  • low affinity: high Kd

New cards
62

competitive antagonist

bind reversibly to the same receptor site as an agonist

do not initiate intracellular effects

rightward shift of dose-response curve

New cards
63

non-competitive antagonist

reduce the magnitude of maximum response that can be attained by any agonist

effects cannot be negated, no matter how much agonist is present

two mechanisms:

  • allosteric site binding

  • irreversible competitive antagonism: orthosteric

New cards
64

biobehavioral interaction

multiple outcomes due to interaction between drugs

  • physiological antagonism

  • additive effects

  • potentiation

New cards
65

tolerance

diminished response to the administration of a drug after repeated drug exposure

New cards
66

cross tolerance

tolerance to one drug can diminish the effectiveness of a second drug in the same class

New cards
67

metabolic tolerance

repeated use of a drug reduces amount of the same drug available at the target tissue

New cards
68

acute tolerance

decrease in response within a single exposure to the drug

  • occurs independently of changes in BAC

  • develops during single administration

    • effects of alcohol during increase are more severe than during elimination

New cards
69

pharmacodynamic tolerance

changes in nerve cell function compensate for continued presence or absence of a drug (e.g. enzyme up-regulation and down-regulation)

New cards
70

behavioral tolerance

tolerance is seen in same environment but reduced in novel environment

New cards
71

operant (Skinnerian) conditioning

may play a role in behavioral tolerance

with repeated exposure and reinforcement, an animal or human can learn to compensate for drug-induced changes in behavior (e.g. the functional alcoholic)

New cards
72

state-dependent learning

tasks learn in the presence of a psychoactive drug may subsequently be performed better in drugged state than non-drugged state

New cards
73

sensitization (reverse tolerance)

enhancement of drug effects after repeated administration of the same dose

some drugs induce tolerance for some effects and sensitization for others

New cards
74

pharmacogenetics

study of the genetic basis for variability in drug response among individuals

goal: identify genetic factors that confer susceptibility to specific side effects or predict therapeutic response

New cards
75

genetic polymorphisms

can influence drug target sites:

  • receptors

  • transporters

  • intracellular signaling cascades

New cards
robot