Psychology 2020A/B Study Guide - Midterm Guide: Opioid Receptor, Drug Tolerance, Psychoactive Drug
27 Apr 2018
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Psych 2020 notes
Drug: chemical compound that may produce psychological, behavioral, and
physiological effects
Psychoactive effects: alterations in cognitive, behavioral and motor processes e.g.
euphoria and hallucinations
Categorization of drugs: alcohol, caffeine, nicotine, cannabis, hallucinogens,
inhalants, major stimulants, sedative-hypnotics, opiates, and steroids
4 names for drugs:
1. Chemical name: uses terms to describe the type of molecule and location of
chemical groups on the molecule
2. Generic/nonproprietary name: commonly used name for a drug
3. Trade/proprietary name: given by a company and can only be used by that
company
4. Street name: often derivates of trade names or refer to some physical aspect
of the drug or some effect
Pharmcokinetics: administration, absorption, distribution, metabolism, and
elimination
Pharmacodynamics: processes involved in the interaction of the drug with receptors
Most common methods of administration: oral, absorption across mucous
membranes or skin, inhalation or pulmonary, or by injection
• Drugs taken orally must pass from the stomach or small intestine into the
bloodstream and a substantial part is metabolized in the liver (first pass
metabolism) before the drug even has an opportunity to produce an effect
• Drugs that are alkaline (bases) become ionized in the stomach and cant pass
out into the bloodstream
• Albert Hoffman found out about trip from LSD when accidently got some of
the drug on his fingers
Inhalants: nicotine, THC and solvents; inhalation of solvents often called huffing or
bagging; when a drug is inhaled it reaches the brain in about -8 seconds faster
than being injected intravenously
• Drugs taken via injection depend on the blood flow in the are of injection
• Mainlining is the term for intravenous injection in the drug subculture
• Skin popping is a term used for subcutaneous injections
• Drugs given by injection or pulmonary route enter circulation by diffusing
through pores in capillary walls
• Drugs taken orally must be lipid soluble to be absorbed from the digestive
system since there are no pores lining the stomach or intestines
Factors that affect the entry of a drug into circulation:
Ionization percentage of nonionized molecules determines the absorption rate,
ionized penetrate cell membranes poorly and are also less fat soluble
• Bases are more easily absorbed as they pass through the digestive system
Lipid solubility lipid soluble compounds penetrate cell membranes more readily
than non lipid soluble ones
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Blood brain barrier protects the brain by reducing diffusion of water soluble and
ionized molecules but doesn’t impede lipid soluble or un-ionized molecules
Receptor binding drugs exert their effects by interacting with receptors, a bond
forms between charged groups in the receptor molecule and oppositely charged
groups on the drug, binding is reversible
Agonist: drug that mimics the effect of a neurotransmitter; binds to receptors,
blocks reuptake, or inhibits metabolic breakdown
Antagonist: compounds, which reduce the effects of a receptor agonist by binding to
active receptors but produce no pharmacological action e.g. Naloxone is an opiate
receptor antagonist
• There are a limited number of receptors to be occupied so if those receptors
are occupied by a weak agonist then even if a stronger agonist is
administered it cannot access the receptors
3 ways to produce agonist activity: block reuptake, bind to the receptor, or interfere
with the enzymes that break down the neurotransmitter
• Drug doses are expressed as milligrams (mg) or given a weight basis mg/kg
Dose-response curve (DRC) most commonly used graphical representation of drug
effects. Vertical axis shows the percent of subjects exhibiting the measured effect
and the horizontal axis shows the dose; allows for comparison of the potency of
drugs
• A more potent drug has a curve to the left of a less potent drug
• There is more than one dose-response curve for each drug because drugs
have more than one effect
ED50: dose that is effective in producing a response in 50% of subjects
LD50: dose which kills 50% of the subjects
Therapeutic index: given by the ration LD50/ED50; the higher the ratio the greater
the difference between the LD50 and the ED50 and the less likely the chance that
lethal or other toxic effects occur
Margin of safety: more conservative measure and is the ratio LD1/ED99; the margin
of safety will always be a smaller value than the therapeutic index
• Tolerance is represented by a shift to the right in the dose-response curve
• Sensitization is depicted by a shift to the left in the dose response curve
• A change in responsiveness to one drug may transfer to other drugs e.g. cross
tolerance and cross sensitization
• Tolerance doesn’t occur to a drug it occurs to the drugs effects and tolerance
develops at different rates to different drug effects
Physical dependence: developed when a chronic user of a drug experiences a
withdrawal syndrome upon cessation of administration
Negative reinforcement: engaging in some behavior that terminates or prevents the
occurrence of some unpleasant event e.g. taking a drug to terminate withdrawal
symptoms
DSM substance use disorder 9 classes: alcohol, cannabis, hallucinogens, inhalants,
opioids, sedative-hypnotics, anxiolytics, stimulants, tobacco and other
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Features of substance use disorder: underlying change in brain circuits that persists
beyond detoxification, cluster of behavioral, cognitive, and physiological symptoms
and the individual continues using the substance despite problems
APA 3 levels of substance use disorder based on the number of criteria exhibited in
each of the 4 categories below:
1. Impaired control
a. Take drugs in larger amounts of for longer period than intended
b. Express persistent desire to cut down but unsuccessful attempts to do
so
c. Spend a lot of time obtaining the substance, using it, or recovering
from its effects
2. Social impairment
a. Failure to fulfill major role obligations
b. Important social activities given up or reduced
c. Continued use despite persistent social or interpersonal problems
3. Risky use
a. Recurrent use in situations/conditions where use is physically
hazardous
b. Continued use despite knowledge of persistent physical or
psychological problems associated with its use
4. Pharmacological criteria
a. Withdrawal symptoms
b. Tolerance
**neither tolerance nor withdrawal are necessary for a diagnosis of substance use
disorder*
Substance use disorders range from mild (2-3 criteria), moderate (4-5) and severe
(6+)
Substance-Induced disorders: reversible substance-specific syndrome that is
causing some level of problem and is due to recent ingestion of a substance
including intoxication, withdrawal, or other disorders (9 classes of drugs plus
caffeine can produce SID’s)
Routes of drug elimination: skin, lungs, kidneys; most important route is via urine
after being metabolized in kidneys
• Liver is the site of enzymatic breakdown which results in metabolites that
are less lipid soluble, larger, carry a greater charge and are inactive/less
active meaning they are less easily reabsorbed to the blood
• Weak acids are excreted more quickly when urine is alkaline and weak bases
are excreted more in urine that is acidic
Elimination half-life: the time needed for half of a drug dose to be eliminated from
the body; relevant to understanding the duration of drug effects
• Takes about 6 half lives for most drugs to be eliminated and person be
considered drug free
• Neuron is the functional unit of the nervous system
Model of synthesis and breakdown of neurotransmitters: 1) precursor substances
are the basic building blocks of neurotransmitters 2) synthesizing agents are needed
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Document Summary
Drug: chemical compound that may produce psychological, behavioral, and physiological effects. Psychoactive effects: alterations in cognitive, behavioral and motor processes e. g. euphoria and hallucinations. Categorization of drugs: alcohol, caffeine, nicotine, cannabis, hallucinogens, inhalants, major stimulants, sedative-hypnotics, opiates, and steroids. Pharmacodynamics: processes involved in the interaction of the drug with receptors. Factors that affect the entry of a drug into circulation: Ionization percentage of nonionized molecules determines the absorption rate, ionized penetrate cell membranes poorly and are also less fat soluble: bases are more easily absorbed as they pass through the digestive system. Lipid solubility lipid soluble compounds penetrate cell membranes more readily than non lipid soluble ones. Blood brain barrier protects the brain by reducing diffusion of water soluble and ionized molecules but doesn"t impede lipid soluble or un-ionized molecules. Receptor binding drugs exert their effects by interacting with receptors, a bond forms between charged groups in the receptor molecule and oppositely charged groups on the drug, binding is reversible.
