Lecture 4: Stimulants and Sedatives Flashcards
Dopamine - Location
Brain and brainstem (substantia nigra, hypothalamus)
Dopamine - receptors
1) ionotropic - none
2) metabotropic:
- D1: Excitatory (K and Ca transport)
- D2: Inhibitory (K and Ca transport)
name the dopamine pathways
1) reward pathway - mesolimbic pathway and mesocortical
2) nigrostriatal pathway
3) tuberoinfundibular pathway
Refer to the slide
coca - scientific name
Erythroxylum coca
coca - part used
leaves
coca - bioactive compound
cocaine
- why is it so addictive
2. risks of cocaine use
- due to effects on dopamine reward pathway
2. risk of stroke, heart attack, lung problems, blood infections, sudden cardiac death
Effects of cocaine with mechanism
loss of contact with reality and profound mental stimulation - more talkative, flight of ideas, reduced need for sleep, and inflated self esteem.
mechanism:
- it interfere with reuptake of dopamine in the mesolimbic dopamine pathway
chronic use of cocaine leads to:
decreased availability of D2 receptors
Norepinephrine (adrenaline) - branch of NS
sympathetic
norepinephrine receptors
1) ionotropic: none
2) metabotropic:
- alpha 1 and beta 1 : excitatory
- alpha 2 and beta 2: inhibitory
ephedra -scientific name
Ephedra sinica
ephedra - parts used
dried stems, root
ephedra - bioactive compound
ephedrine, pseudoephidrine
ephedrine - mechanism
- it is a CNS stimulator
1. it enters pre - synaptic neutron via the norepinephrine transporter
2. enters the synaptic vesicle via the vesicular monoamine transporter
3. norepinephrine is released into cytoplasm and released into the synaptic cleft by norepinephrine transporter
Purines - receptors
- ionotropic : P2X receptors - found in neurons and glial cells in the PNS and CNS (ATP)
- metabotropic:
- P1: Adenosine - found in brain, heart, kidneys, and adipose tissue
- P2Y: ATP, ADP, UTP, UDP - found in brain, heart, kidneys, and adipose tissue
- P1: Adenosine - found in brain, heart, kidneys, and adipose tissue
in the CNS , ATP and adenosine play an important role in ——–
sleep
sleep and adenosine levels
extracellular levels of adenosine in basal forebrain is lower during sleep and higher during sleep deprivation
adenosine decreases the activity of ————
cholinergic neurons
adenosine regulation of sleep is mediated by —- and —- receptors
A1,A2
Adenosine levels and ATP
increase in adenosine levels reflects an increased breakdown of ATP
caffeine acts as an —— for all adenosine receptors
antagonist
caffeine primarily binds to the —– receptors
A2a
long term exposure to caffeine
it blocks the effects of adenosine, norepinephrine may be reduced and the brain relies on caffeine to remain alert
coffee - scientific name
coffea arabica
coffee - parts used
seeds
coffee - bioactive compound
caffeine
tea - scientific name
camellia sinensis
tea - parts used
leaves
tea - bioactive compound
Epigallocatechin gallate (EGCG)
Cocoa - scientific name
Theobroma cacao
Cocoa - parts used
seeds
cocoa - bioactive compound
Theobromine
Yerba Mate - scientific name
Ilex paraguariensis
Yerba Mate - parts used
leaves and stem
Yerba Mate - bioactive compound
Theobromine
heavy use of Yerba Maté
increased incidence of esophageal cancer,
Guarana - scientific name
Paullinia cupana
Guarana - parts used
seeds
Guarana - bioactive compound
Caffeine
Rank the following from the most caffeine content to the least:
Tea, cocoa, coffee, Yerba Mate, Guarana
- Guarana
- Tea
- Coffee
- Yerba Mate
- Cocoa
overdoes of caffeine occurs at:
> 400 mg
symptoms of caffeine intoxication
restlessness, fidgeting, anxiety, insomnia, excitement, flushing, increased urination, GI disturbance, muscle twitching, irritability, irregular or rapid heart bear, rambling flow of through and speech
* comparable to other stimulants
ways through which herbal sedatives work
- they must either cause neuron inhibition or inhibit the neuronal pathway
1. GABA receptor agonist: GABAa receptors have allosteric binding sites for bento, barb, certain steroids and ethanol; can also enhance GABA activity by blocking its reuptake or increasing its release
2. glutamate receptor antagonist: inhibition of NMDA may explain why does sedatives impair memory. other excitatory receptor are AMPA, kainite and metabotropic glutamate receptors (mGluR)
3. Blocking of voltage gated ion channels: *predominantly anti-seizure drugs
Valerian - scientific name
Valeriana officinalis
Valerian - parts used
Roots and rhizomes
Valerian - bioactive compound
valerenic acid
main components of valerian that have a synergistic activity
- monoterpenes
- Sesquiterpenes
- Alkaloids
Refer to the slides for examples of each
likely mechanism of action(s) of valerian
- facilities GABA release and reversal of uptake
2. inhibition of GABA breakdown
promising evidence that Valerian can improve —–
It also may be useful in treating —–
sleep, anxiety
Chamomile - scientific name
Matricaria recutita
Chamomile - parts used
dried flowers
Chamomile - bioactive compound
Apigenin
apigenin - mechanism of action(s)
- as a monoamine transport activator
2. as a ligand for benzodiazepine receptors on GABAa - thus, enhancing the effect of GABA
Kava - scientific name
Piper methysticum
Kava - parts used
Rootstalk
Kava - bioactive compound
Kavain
mechanism(s) of Kava
- GABA: facilities GABA transmission
- Voltage gated ion channels: inhibits sodium channels and subsequent release of glutamate
- Monoamine: Kavalactones inhibit monoamine oxidase B and reduce inflammation
- Eicosanoids: Kavain inhibits cyclooxygenase (COOX), suppressing synthesis of thromboxane A2. In turn, lower thromboxane A2 increases GABA function.
Kava’s psychotropic effect is due to:
combination of its phytochemicals
name 6 herbal sedatives
- Chamomile
- Kava
- Valerian
- Passion flower
- Catnip
- Hops
Chorea
a neurological disorder characterized by jerky involuntary movements affecting especially the shoulders, hips, and face
Tics
a habitual spasmodic contraction of the muscles, often in the face
Athetosis
a condition in which abnormal muscle contractions cause involuntary writhing movements. It affects some people with cerebral palsy, impairing speech and use of the hands
diuretic
causing increased passing of urine
