Chapter 6 - Drugs & Hormones Flashcards
Psychoactive Drugs
substances that act to to alter mood, thought or behavior
- for recreation (make it abnormal)
- to manage neuropsychological illness (make it normal)
Drug Routes
safest → least safe
high dose → low dose
- stomach
- intestines
- skin
- muscles
- lungs
- injected into:
- blood
- CNS
- receptors
Drug Routes
- characteristics of psychoactive drugs
water-soluble → to pass BBB
diluted in body
weak acids: stomach → bloodstream
weak bases: intestines → bloodstream
Blood-Brain Barrier
- characteristics
- passage of substances
brain capillaries have tight junctions covered by astrocyte feet
small uncharged molecules diffuse across
- CO2 & O2
active transport
- aa’s, glucose, fats
large, charged molecules can’t leave capillary
Blood-Brain Barrier
- (3) areas not protected
1) Pituitary Gland
2) Pineal Gland
3) Area Postrema (induces vomiting)
Drug Effects vs. Actions
EFFECTS → changes in mood/thought/behavior
ACTIONS → changes in neurochemistry
Drug Actions
affect stages of chemical transmission
synthesis, storage, release, activation, inactivation, reuptake/degradation
Agonist vs. Antagonist
Agonist
increases synapse functioning
- ↑ synthesis, storage, release
- aids binding/mimics
- ↓ inactivation/degredation/reuptake
Antagonist
decreases synapse functioning
Classification of Psychoactive Drugs
- (5)
based on drug effects
I. Sedatives & Antianxiety Agents
II. Antipsychotic Agents
III. Antidepressants
IV. Narcotic Analgesics
V. Psychomotor Stimulants
I. Sedatives & Antianxiety Agents
GABA agonists
cross-tolerance
anxiety relief, disinhibition, sedation, sleep, anesthesia, coma
Antianxiety Agents → less drastic effects but short-term use
I. Sedatives & Antianxiety Agents
-
Sedatives (2)
- actions & effects
- dose (2)
(INCREASE TIME PORE IS OPEN)
→ dose-dependant relationship
- anxiety relief, disinhibition, sedate, sleep, anesthesia, coma
tolerance develops with frequent use
a) Alcohol
* ↑ GABA binding
b) Barbiturates
* mimic GABA → binds to receptor → ↑ Cl influx
I. Sedatives & Antianxiety Agents
-
Antianxiety Agents
- actions & effects
a) benzodiazepines (Valium, Xanax)
Action: ↑ GABA binding → ↑ frequency of pore opening
- indirectly ↑ Cl influx
Effects: anxiety relief
Why are Benzodiazepines safer & harder to overdose on than Barbiturates?
Barbiturates → mimic GABA, ↑ Cl influx directly
Benzodiazepines → ↑ GABA binding, ↑ Cl influx indirectly
- limited by amount of GABA
II. Antipsychotic Agents
- Effects (2)
- Action
Antipsychotics (neuroleptics): Haloperidol, Chloropromazine (FGAs)
→ Dopamine (DA) antagonists
SGA’s - also block seratonin receptors
EFFECT → ↓ psychosis symptoms (hallucinations, delusions)
- side-effect: dyskinesia → impaired motor control (like Parkinsons)
ACTIONS: blocks D2 DA receptors
DA Hypothesis of Schizophrenia
- support?
IDEA: excess DA activity causes schizophrenia symptoms
supported by similar symptoms in chronic amphetamine (DA agonist) users
III. Antidepressants (3)
- Effects
seratonin agonists
a) monoamine oxidase (MAO) inhibitors
b) Tricyclic Antidepressants
c) Selective Serotonin Reuptake Inhibitors (SSRIs)
↓ Depression symptoms
- guilt, worthlessness, disruption of eating/sleep, slowing of behavior, suicidal thoughts
III. Antidepressants
-
Drug Actions
- MAOIs
- Tricyclic Antidepressants
- SSRIs
1) ↑ NE & seratonin (& DA)
* block deactivating enzyme in axon terminals
2) ↑ NE & seratonin
* block reuptake
3) ↑ seratonin
* ↑ hippocampal neurogenesis
III. ANTIDEPRESSANTS → MAOIs
- food-drug interactions
↑ availability of monamines
- precursors in diet
- tyramine → ↑ BP
III. Antidepressants
- Why do effects take weeks to work?
metabotropic receptors → ↑ transcription of BDNF
→ facilitates rebuilding of brain & neuron health
- ↓ cell death
- ↑ neurogenesis in certain areas
-
hippocampus →turns off stress response
- relief from depression symptoms
-
hippocampus →turns off stress response
IV. Narcotic Analgesics
- effects (2)
natural or synthetic drugs derived from opium poppy
→ opium, codeine, morphine, heroin
↓ GABA release → ↑ DA (addictive)
narcotic → sleep-inducing
analgesic → pain-relieving
IV. Narcotic Analgesics
- drug actions
act on endorphin (endogenous morphine-like receptors) receptors in brain
V. Psychomotor Stimulants
- (3)
a) Behavioral Stimulants
b) General Stimulant
c) Psychedelic Drugs
V. Psychomotor Stimulants (Psychotropics)
a) Behavioral Stimulants
- effects
- actions
→ agonists
cocaine - ↑ DA, NE, seratonin
amphetamine - ↑ DA, NE
effects: ↑ motor behavior, mood & alertness
actions:
- block DA reuptake
- ↑ DA release (amphetamine)