Week 5 - Drugs and Toxins

EXAM 2

drugs and toxins must be introduced to the

bloodstream to interact with the brain and the body.

impacts only tissues that

interact with the substance

tissues usually affected

ones with ligands binding to receptors

our body reuses

chemical signals

the substance’s effect is based on

dose and route of administration

more of a substance,

greater effect on the body

effective and fatal doses vary

between substances

greater dosage,

greater effect

opioids

pain killers

codeine (oral) dose

110 mg

morphine (oral) dose

10 mg

oxycodone (oral) dose

6.67 mg

most direct path of administration to the target tissue will

have the greatest effect

5 routes of administration

-ingestion

-absorption

-intramuscular injection

-inhalation

-intravenous injection

morphine (IV) dose

3.33 mg

fentanyl (IV) dose

0.1 mg

fast acting methods must have a smaller dose because there is

less time to be broken down

astrocytes tightly wrap around

blood vesicles in the brain

materials must pass through the astrocytes before

reaching the neurons

the BBB allows in

glucose, oxygen, water, amino acids

the BBB blocks

waste and toxins

absorption

through your pores and membrane

ingestion

eating

intramuscular injection

injection into the muscle and spreads around your body (ex: flu shot, covid shot)

inhalation

snorting

intravenous drugs

injection straight into the vein, quickest and must use the smallest dose

small and unchanged substance can still slip through the BBB to

interact with the CNS

drugs and toxins that interact with the brain are

able to pass through the BBB

medications that can pass through the BBB

benadryl and claritin

benadryl

diphenhydramine is an allergy medication (antihistamine) that reduces mucus

mucus producing cells in our sinuses are regulated by

histamine receptors

when histamine binds to histamine receptors,

mucus is produced

antihistamines are

antagonists

antagonists

molecules that bind to a receptor but don’t activate the receptor

prevents histamine from binding and

activating the receptors

histamine is an

NT that activates receptors in our brain that keep us awake.

antihistamines block histamine receptors resulting in

drowsiness and exhaustion

claritin

loratidine is an antihistamine with a similar ligand that has a different structure and is slightly charged.

claritin being larger and slightly charged prevents it

from passing through the blood brain barrier to prevent the antihistamine from entering your brain and interacting with the histamine receptors (don’t make you sleepy)

NMJ

neuromuscular junction

skeletal muscles are made of

many parallel muscle fibers

muscle fibers contract when stimulated by

axons

PNS neurons of the somatic efferent division have axons

that synapse with each muscle fiber

presynaptic axon releases

acetylcholine (ACh)

postsynaptic muscle fiber contracts when

ACh binds to ACh receptors

botulinum toxin is a

neurotoxic poison found in bacteria due to mishandled meat

botox breaks down the

SNARE complex and prevents it from oeprating

botox makes the PNS axon unable to

release NTs without intact SNARE complexes

muscle fibers will not receive NTs when

the axon is not stimulated

muscle fiber is

permanently paralyzed

ingesting a high dose of botox allows the toxin to enter the bloodstream and spread to

NMJs and cause botulism and possible death

local injection of a low dose of botox to

a specific muscle will not spread to the bloodstream

localized botox injection leads to

a localized muscle paralytic

cosmetic botox uses

paralyzes small face wrinkles in skin

botox as a tension headache treatment

weakens overly constricted muscles around the base of the skull, relieving tension from a headache

strabismus treatment

lazy eye caused by muscles of the eye unevenly pulling on the eye, treated by weakening muscles on the tenser side to make them even

hypotropia

eye points downward

hypertropia

eye point upward

exotropia

eye points outward

esotropia

eye points inward

reuptake inhibitors

commonly prescribed medications that influence synaptic transmission by modulating the activity of NT reuptake proteins

SSRIs

selective serotonin reuptake inhibitors

SSRIs are typically prescribed for

major depressive disorder and generalized anxiety disorder

why postsynaptic activity is influenced if 5-HT receptors are inhibited

the synapse will take longer to clear all 5-HT out from the cleft

the synapse still has some functioning

5-HT uptake proteins, degradation proteins, and diffusion

SSRI’s increase the amount of time

5-HT is in the synaptic cleft

SSRIs staying in the synaptic cleft for longer leads to

5-HT having more opportunities to bind and unbind from 5-HT receptors resulting in increased postsynaptic activation

belief that people that are on SSRIs have

decreased 5-HT signaling (less serotonin)

SSRI’s take how longer to start working

around 3 weeks

beneficial outcomes of SSRIs are due to

presynaptic changes following prolonged increase of 5-HT signaling

cocaine

an illegal recreational drug that inhibits the reuptake of dopamine (DA), norepinephrine (NE), and serotonin (5-HT)

cocaine has an almost identical mechanism to

SSRIs

cocaine is a stimulant that leads to

hyperactivity, euphoria, and emotional dysregulation

SSRIs and cocaine have different behavioral effects because they influence

the signaling of different NTs

serotonin does not lead to

hyperactivity, euphoria, and emotional dysregulation like dopamine and norepinephrine do

neural activity is dependent on the activity of

receptors in the brain

modulating different NT signaling in the brain will effect those

receptors, having different effects on behavior

methylphenidate

commonly known as ritalin prescribed for ADHD with the same activity component as cocaine.