Drugs and the Brain Flashcards
Chemical transmission
the steps it takes for a drug to exert its effects
steps. ..
- synthesis of NT
- Storage of the NT
- Breakdown of the cytoplasm
- Exocyst
- Autorecptor feedback on the pre-synaptic cleft
- Activation of the post-synaptic receptors by NT
- Deactivation of the NT
Define Agonist
enhance activity of neurotransmitter for which they are agnostic
-agnostic effects: accomplished by drug binding to receptor site imitating the NT that should be there
what does Nicotine do as an agonist?
What does Cocaine do?
- ex/ nicotine binds to NT Ach, binding to the nicotinic receptors producing a stimulant effect
- ex/ cocaine blocks re-uptake of NT by pre-synaptic neuron causing DA and NE to hang around
Define Ant-agnostic
diminish or decrease neurotransmitter activity
- accomplished by drug binding to NT site and blocking NT that should be there but having no effect
- prevent appropriate NT from getting in
How does Curare and Botox effect NT’s
How does Botulinum toxin effect NT’s (both ant-agnostic)
Curare and Botox:
antagonists for the NT Ach and they block Nicotinic receptor site at the muscular junctions. For Botox and curare they prevent muscles from moving and cause paralyzing effects.
Botulinum Toxin: NT Ach, inhibiting release of ACh from pre-synaptic nueron thereby decreasing the amount of available ACh in those synapses and causes paralysis
What are the 6 Agnostic effects?
- drug serves ad a precursor for NT
- Drugs stimulates the release of NT
- Drug stimulates post-synpatic receptors for NT
- Drug blocks pre-synaptic autoreceptors for NT
- Drug blocks reuptake of NT
- Drug inactivates breakdown enzyme for NT
What are the 5 Antagonistic effects?
- Drug prevents storage of NT in synaptic vesicles
- Drug inhibits release of NT
- Drug blocks post-synaptic receptors for NT
- Drug inactivates synthetic enzyme for NT
- Drug stimulates autoreceptors for NT
CAPILLARIES OF THE BRAIN
- more compact tightly together, watersolluable substances cannot pass through
- only lipid-soluable substances can pass the lipid capillary wall
GLIAL CELLS
- if a substance is able to move through the capillary wall, it encounters yet another barrier
- 85% of capillaries in brain covered with glial cells resulting in very little extracellular space next to the blood vessel walls.
- very difficult to get thru blood brain barrier
- need active transport system
- some drugs enter brain through passive transport ( heroine, nicotine, alcohol) down concentration gradient from bloodstream to the brain - the extent of these drugs effect on BBB shows drugs influence on psychological process
babies and BBB
- blood brain barrier is not fully developed until 1-2 years of age
- infants exposed to drugs or alcohol have a heightened effect
- born with addictions, if exposed to drugs in womb
Define Pharmacokinetics
the movement (kinetics) of Drugs (pharmaco) -process by which dugs are absorbed, distributed in body, metabolized, and excreted
Administration of Drugs through Injection:
SUBCUTANEUOUS: Needle is inserted just under the skin
INTRAMUSCULAR: Needle inserted into a muscle (often upper arm or buttock muscle). Depot Injection is a special type of injection which the vehicle is oil, slowing diffusion of the drug in the body fluids
INTRAPERITONEAL: Needle is inserted through the abdominal wall into peritoneal cavity which is the area surrounding the intestines, liver, stomach, and other abdominal organs
INTRAVENOUS: Needle is inserted through vein, so drug moves directly into blood stream
non injection methods of drugs administration:
Oral
Intrarectal
Inhalation
Topical
Injection methods that by pass Blood Brain Barrier
INTRACEREBRAL
INTRACEREBROVENTRICULAR
INTRATHECAL
Dose response curve:
and how to use it to compare effectiveness of drug
Definition: a graph of the magnitude of a drug as function of the amount of drug administered
- compares effectiveness of different drugs and compare the dose at which 50% of subjects who receive each drug experience the effect under investigation
- (ED50=effective dose) (LD=Lethal dose)