BNS - Psychopharmacology Flashcards
Define drug
An exogenous chemical not necessary for normal cellular functioning that significantly alters the functions of certain cells of the body when taken in relatively low doses
Define site of action
Points at which molecules of drugs interact with molecules located on or in cells of the body, thus affecting some biochemical processes of these cells
Routes of drug administration (9)
- Intravenous injection
- Intraperitoneal injection
- Intramuscular injection
- Subcutaneous injection
- Oral administration
- Inhalation
- Topical administration
- Intracerebral administration
- Intracerebroventricular administration
Lipid solubility
- Determines rate at which drug reaches sites of action in the brain
- Blood brain barrier works only for water soluble molecules, so molecules that are soluble in lipids pass through cells lining the capillaries in CNS, and rapidly distribute throughout the brain
How to measure effectiveness of a drug
Plot a dose-response curve
Drug response curve
- Subjects get various doses of a drug (mg/kg of body weight)
- Heavier subject – more widely distributed drug
- Increased doses until a point of maximum effect is reached; then increasing dose of the drug does not produce any more effect
Therapeutic index
Ratio for two numbers between Dose that produces desired effect in 50% of sample; and Dose that produces toxic effect in 50% of sample
(Lower the therapeutic index, the more care must be taken in prescribing the drug)
Affinity of a drug
Readiness with which the two molecules join together
Two drugs with identical sites of action can vary in effectiveness if they have different affinities for binding sites
Drug tolerance
- A decrease in the effectiveness of a drug that is administered repeatedly
- Result of body’s attempt to compensate for the effect of drug
Drug sensitization
An increase in the effectiveness of a drug that is administered repeatedly.
Withdrawal symptoms
The appearance of symptoms opposite to those produced by a drug, when the drug is administered repeatedly and then suddenly no longer taken.
Eg: heroin
Placebo
An inert substance that is given to an organism instead of a physiologically active drug; used experimentally to control for the effects of mere administration of a drug.
Has no SPECIFIC physiological effect
Antagonist
A drug that opposes or inhibits the effects of a particular neurotransmitter on the postsynaptic cell
Agonist
A drug that facilitates the effects of a particular neurotransmitter on the postsynaptic cell
Types of drug tolerance
Metabolic
Cellular
Learned
Define neurotransmitters
Have modulating effects rather than information-transmitting effects; tends to activate or inhibit entire circuits of neurons that are involved in particular brain functions
Ach is found in which parts of the brain & functions
Dorsolateral pons (REM sleep) Medial septum (memory - hippocampus) Basal forebrain (learning)
Drugs that affect ACh release
Botulinum toxin (botox) - antagonist Black widow spider's venom - agonist
Drugs that affect ACh receptors
Nicotine - affect on ionotropic receptor (mostly in PNS)
Muscarine - affect on metabotropic receptor (mostly in CNS)
Drugs that block Ach receptors
Atropine - blocks muscarinic receptors (used in surgery)
Curare - blocks nicotinic receptors (causes paralysis)
Three major dopaminergic pathways
Nigrostriatal system (in substantia nigra) Mesolimbic system (in ventral tegmental area) Mesocortical system (in ventral tegmental area)
Functions of dopamine
Movement, attention, learning, and the reinforcing effects of drugs that people tend to abuse
Drugs affecting dopamine
L-dopa, amphetamine, reserpine, methamphetamine, cocaine, and methylphenidate (Ritalin), Chlorpromazine
Location of serotonin
Raphe nuclei of the midbrain, pons, and medulla
Dorsal and medial raphe nuclei project axons to the cerebral cortex
Function of serotonin
- Regulation of mood; in the control of eating, sleep, and arousal; and in the regulation of pain.
- Also in control of dreaming
Drugs involved with serotonin
Fluoxetine (Prozac)
Fenfluramine
LSD
MDMA
