neuropharm lecture 1 Flashcards
What is pharmacology?
the scientific study of the actions of drugs and their effects.
What is neuropharmacology?
the scientific study of drug-induced changes in the functioning of the brain.
What is psychopharmacology?
the scientific study of drug-induced changes in mood, thinking and behavior.
What is Neuropsychopharmacology?
objective is to identify chemical substances that act upon the nervous system to alter behavior that is disturbed due to injury, disease, environment.
What are psychoactive drugs?
are any chemical substance capable of changing your brains function, and which results in alterations in perception, mood, consciousness, cognition, and/or behavior.
What is drug action?
specific molecular changes produced by a drug when it binds to its target site or receptor (neuropharmacology).
What is drug effect?
widespread alterations in physiological and psychological function produced by a drug (psychopharmacology).
Therapeutic effect vs. side effect
Therapeutic Effect: drug-receptor interaction that produces desired physical or behavioral change.
Side Effect: anything else.
Can range from mild to severe;
Many people take drugs for their “side effects” (e.g. amphetamines for weight loss).
Specific effects vs nonspecific effects
Specific effects: those based on the physical and biochemical interactions of a drug with a target site.
Nonspecific effects: based not on chemical activity but on unique characteristics of the individual.
Experience, mood, expectations, attitude, genetics.
E.g. placebo
Pharmacokinetics
the study of how drugs move through your body.
factors that contribute to how a drug moves through your body:
1.Route of administration;
2.Absorption & distribution;
3.Binding;
4.Metabolism/inactivation;
5.Elimination/excretion.
Possible routes of administration:
-Oral;
-Intravenous (IV);
-Intraperitoneal (IP);
-Subcutaneous (SQ);
-Intramuscular (IM);
-Inhalation.
What is Oral administration and what are its advantages and disadvantages?
Oral administration is the consumption of drugs via mouth (e.g. prescription pills, MDMA pills, THC gummies).
Advantages:
-Safest, most convenient and economical;
-Self administered.
Disadvantages:
-Individual differences make it difficult to know how much drug will be absorbed into blood stream (genetics, food in stomach, etc.);
-Stomach acids destroy drugs rapidly;
-Least efficient.
What is Intravenous (IV) and what are its advantages and disadvantages
IV administration is injecting drug/substance directly into the venous blood stream.
Advantages:
-Dosages can be extremely precise;
-Extremely fast onset of pharmacological action;
-Less strain on liver.
Disadvantages:
-Extremely dangerous;
-Very few barriers between drug and brain, gives very little time for intervention (should it be required);
-Requires (or should require) a health care professional for administration.
What is Intramuscular (IM) and what are its advantages and disadvantages?
IM administration is directly into the (skeletal) muscle tissue.
Advantages:
-More rapid absorption than from the stomach (but less than IV);
-Absorption is more gradual (tends to form a pocket, slowly diffuses);
-Can be combined with other drugs to further control of absorption (e.g. immunosuppressant, oil).
Disadvantages:
-Rate of absorption depends on rate of blood flow to that specific muscle tissue;
-It hurts!
What is Subcutaneous (SQ) and what are its advantages and disadvantages
Absorption is slow and steady but can be variable.
Depends on derma layers, adipose
layers, blood flow to that particular area,
etc.
Can use pellet or other delivery device.
E.g. Insulin bolus, osmotic mini-pumps.
What are Epidural Injections
Nerve fibers that travel up and down the spinal cord bring sensory information back-and-forth between the brain and the periphery (arms, legs, neck, etc.)
Injecting drugs into the epidural space can temporarily mute communication from these nerves.
Inhalation
Most preferred route of administration for recreational drug use (e.g. tobacco, nicotine, cannabis, cocaine, heroin, etc.)
Lungs have very large surface area which allows for extremely rapid absorption of drugs into the blood stream.
Blood capillaries of the lungs go straight to the brain!
Blood leaving lungs is already oxygenated;
First priority for oxygenated blood à deliver oxygen to brain.
What is the fastest way to get drugs to the brain?
Inhalation
Intranasal and Sublingual
Using the mucous membranes in both your nose and mouth, drugs can gain access to your blood stream.
Intranasal (aka insufflation) = snorting cocaine powder.
Sublingual = dropping LSD tablets
Transdermal
Transdermal patches (e.g. nicotine patch, fentanyl patch) provides a slow, continuous, and highly controlled release of a drug.
Allow for continuous absorption of drugs over hours, or days.
Safe (but slow).
Some factors that influence
how we absorb drugs.
-Transport across (phospholipid bilayer) membranes;
-Lipid (in)solubility;
-Ionization of drugs (polar vs. non-polar; hydrophobic vs. hydrophilic);
-Genetic differences at every step along the way;
-Current metabolic and homeostatic state.
How are drugs distributed across the body?
There are many factors and membranes in your body that serve to regulate which drugs gain access to which parts of the body.
Blood circulation: regions of the body that are more vascularized get the most drug (brain, skeletal muscle > fat);
Solubility of drug in fat;
Binding of drug to proteins in blood stream (e.g. chaperones);
Permeability of membranes.
What are capillaries?
Capillaries are small blood vessels that are the site of exchange of many substances between the arterioles and venules.
Small pores that allow transport of chemicals regardless of their solubility;
Protein-bound drugs cannot pass through capillaries.
Brain capillaries have distinct morphology:
No clefts or pinocytic sites;
Movement of water-soluble molecules is minimized.
