Bio Psych Exam #3 Flashcards
Psychopharmacology
the study of drugs that affect the nervous system and behavior
What is a drug?
An exogenous (made outside of the body) chemical not necessary for normal cellular functioning that significantly alters the functions of certain cells of the body when taken in relatively low doses
(exogenous, low doses, not necessary
Drugs and behavior
The changes a drug produces in an animal’s physiological processes and behavior
- Ex: morphine/heroine and other opioids are pain relievers
Drugs have sites of action
each drug has a unique effect and a site of action
**Ex: there are specialized receptors for opioids; when molecules of heroin activate these opioid receptors the activity of the neuron changes
Pharmacokinetics
what the body does with the drug
Absorption types
1) Intravenous (IV) injection - into a vein
2) Intraperitoneal (IP) injection - into space surrounding stomach, liver → usually in animals
3) Intramuscular injection (IM_: vaccines
4) Subcutaneous injection (SC) = into the space beneath the skin
5) Orally = swallow pill
Sublingual - under the 6)tongue
7) Inhalation - smoked
8) Intranasal - snort
9) Topical - into skin
Cocaine absorption
1) IV: strong high immediately
2) smoking: similar to IV, less higher
3) snorting: takes a bit to kick in, less high but lasts longer
4) oral: takes an hour to kick in, less high but lasts very long
Oral dose vs. Sublingual
1) Oral: Has to go through many steps to get to the brain
2) Sublingual: under the tongue
- Dissolve and can get into the blood system immediately: travel through the capillaries in your mouth
Goes to the brain almost immediately
Distribution of drugs within the body
After absorption, the drug distributes to interstitial and intracellular fluids → depends on some physiological factors and physicochemical properties
Body parts with high drug distribution
The liver, kidneys, brain, and other well-irrigated (have the most blood supply) organs receive most of the drug
Body parts with low drug distribution
Release to muscles, most viscera, and adipose tissue (fat) is slower
What prevents drugs from getting to the brain?
- Blood-brain barrier: a barrier that restricts the indiscriminate access of certain substances in the bloodstream to the CNS
- A layer of astrocytes that prevents substances in the circulating blood from freely entering the extracellular fluid of the brain
lack of blood brain barrier in:
1) Pituitary gland
2) Pineal gland (day/night cycle) → drugs can easily impact sleep
3) Area postrema (vomit toxic substances): in the brain stem
Metabolism
Set of reactions and transformations that drugs undergo in the body
Excretion
Elimination by the body of residues of drug metabolism
Kidney and excretion
Take blood and filter out waste products
**most important excretory organ
Excretion pathways
1) Renal (kidneys)
2) Biliary (bile) and fecal (poop)
3) Pulmonary (lungs)
4) Sweat, saliva, and tears
5) Breast milk
Dose response curve
Systematically titrate the dose of the drug: see what the effect of the drug is at each dose
Left: The dose is too low to have any therapeutic benefit
Right: point where the dose plateaus → If you give the patient a larger dose, the therapeutic benefit does not increase
The margin of safety on a dose response curve
1) The effective dose (orange)
2) Where it becomes lethal (purple) → opioids will stop respiration
Tolerance
A decrease in the effectiveness of a drug administered repeatedly
- Once someone has developed tolerance, they will likely show withdrawal symptoms
- Decrease in effectiveness of binding, **receptors become less sensitive or receptors decrease in overall numbers
Sensitization
An increase in the effectiveness of a drug that is administered repeatedly
Less common than tolerance
Can get both tolerance and sensitization
Example of sensitization and tolerance
Example: movement effects of cocaine show sensitization → repeated use leads to movement disorders./convulsions whereas euphoric effects don’t show sensitization, maybe even tolerance
Can develop tolerance to the euphoria
Can develop sensitization for movement disorders
Agonists
A drug that mimics or facilitates the effects of a neurotransmitter on the postsynaptic cell
- a drug that helps the system
Birth of agonists
some neurotransmitters need raw/precursor materials
*If we administer more of the precursor, we get more neurotransmitters → our effects are enhanced