Download Main mechanisms for drug action

Lecture 3
Part 2
Main mechanisms for drug action
NT _______________
Can reduce or enhance the amount of NT produced
Either reduces or enhances the action of that NT, respectively
If it interferes early enough, it could effect multiple NTs (ie dopamine turns into
norepinephrine and epinephrine)
NT _______________
Can reduce the amount of NT stored
Causes less NT to be available for release
NT _______________
Can promote or prevent NT release
Agonists promote
Antagonists prevent
Different Effects of Drugs
_______________Effects
Mimic the action of NTs
Agonists: act just as the NT would, activating the receptors
Antagonists: bind to the receptor without activating it, but blocking the NT from
binding (like gum in a key hole)
_______________Effects
Reuptake inhibitors
Attack the enzymes responsible for the deterioration of NTs in the synaptic cleft
Physiological responses to drugs
The body likes things to remain _______________
Will change and adapt to keep things as constant as possible
TOLERANCE
Must take _______________of the substance to achieve the same effect
“One dose of meth on the first day of use will trigger euphoria and energize the
user to a level that can only be matched by 20 doses on the 100th day of use”
Tolerance
Some tolerance develops with _______________drug use
Large amounts of the drug cause tolerance to develop faster
Tolerance will return to _______________if drug use stops
Reestablishes more quickly if use picks up again though
Types of Tolerance
______________________________Tolerance
Body tries to break the drug down more quickly
Increases metabolism
Pharmacodynamic Tolerance
Nerve cells change connections and receptors that decrease sensitivity
______________________________Tolerance
Trying to compensate for drunken feelings and behaviors
More types of tolerance
_______________Tolerance
User becomes more sensitive to the drug
The drug may destroy tissue
User becomes older and is more sensitive
An alcoholic with no liver
Needs very little alcohol to remain drunk
_______________Tolerance
Adapting to the drug instantly
Some people survive huge amounts of a drug- well beyond the normal lethal dose
this way
Three more types of tolerance
_______________Tolerance
Tolerance to the mental or physical effects of the drug, but not to both
Sleeping pills cause sleep (physical) and euphoria (mental)
Tolerance develops for the mental effects but not the physical
_______________Tolerance
Much faster form of reverse tolerance
Cross-tolerance
Tolerance to one drug causes tolerance to another to develop
Heroin addicts are tolerant to morphine
Tissue Dependence
Biology of user changes
Depends on the _______________to stay functional
Livers of alcoholics have way more mitochondria (to metabolize all of the extra alcohol)
If none comes, major withdrawal can occur
Cross-dependence can occur too
Dependence to one drug = dependence to another
Other major terms
Psychological ______________________________
The altered state that drugs cause is pleasurable to the user
Withdrawal
Once tolerance develops, the body tries to rebalance everything
_______________: physical signs of withdrawal are obvious
_______________: no obvious physical signs
May be based on expectations
Maybe be used to get more drugs an sympathy from doctors or family
Protracted Withdrawal
______________________________ induced by environmental cues
Tolerance develops to the drug and the situation/social aspects of using
After dinner, many ex-smokers crave cigarettes and experience increased
withdrawal symptoms years after they have quit
Theories of Addiction
In the past
Addiction was viewed as a ______________________________
Currently
Many factors seem to play a role
_______________
Environmental
Addictive disease model
“_______________model”
Addiction due to
_______________irregularities
Abnormal brain chemistry
Abnormal brain anatomy
Certain drugs enhance these problems
Most experts believe the genetic influence is 40-60%
Behavioral/environmental model
Environmental factors change _______________chemistry
PTSD may lead users to seek out drugs
Chronic _______________may play a role too
Academic model
The body adapts to the toxic effects of drugs at the chemical level
Explains ideas like:
_______________
Dependence
_______________
Diathesis-stress theory of Addiction
Two components:
A _____________________________ (typically biological) to develop addiction
An environmental stressor to trigger the addiction
User must have _______________to be an addict
What do we know about genetic influences?
Definite signs of genetic influences on addiction
_______________studies
Alcoholic parents 34% _______________likely to have alcoholic children than
non-alcoholic parents
Compulsivity gene: _______________deficiency syndrome
Book lists many more genes linked to various drug addictions
Experiences change brain connections and development
_______________
Experience with drugs
Changes linked to increase in cravings and addictive behaviors
Mice studies of addiction
Alcohol _______________mice vs. alcohol _______________mice