opioids Flashcards
(21 cards)
What are the three types of opioids?
Naturally occurring (e.g., morphine, codeine), semisynthetic (e.g., heroin, hydrocodone), and fully synthetic (e.g., fentanyl, LAAM).
What plant do natural opioids come from and what substances does it produce?
The poppy plant, which produces a latex milk containing morphine and codeine.
What makes heroin more potent than morphine?
Heroin is a semisynthetic opioid made by deacetylating morphine, increasing its lipid solubility and potency.
What is unique about fully synthetic opioids like fentanyl?
They are not structurally related to morphine or codeine and do not use any naturally occurring opioids.
How are opioids absorbed and metabolized?
They are lipid-soluble and easily enter the brain. They are primarily metabolized in the liver and produce biologically active metabolites.
Which opioid crosses the blood-brain barrier faster, heroin or morphine? Why?
Heroin, due to added acetyl groups increasing lipid solubility.
What are the three propeptides that endogenous opioid neuropeptides derive from?
Proopiomelanocortin (POMC), proenkephalin, and prodynorphin.
What are the three main opioid receptors and their effects?
Mu: Euphoria, constipation, reduced inflammation
Delta: Convulsions, constipation
Kappa: Dysphoria, reduced inflammation
All produce analgesia.
What kind of receptors are opioid receptors and what is one of their main inhibitory effects?
G protein-coupled metabotropic receptors that activate inwardly rectifying potassium channels to inhibit neurons.
Where is the opioid system most active in the CNS?
In areas like the thalamus, nucleus accumbens, and amygdala.
How do opioids affect dopamine and GABA in reward pathways?
They inhibit GABA, which increases dopamine release in areas like the VTA and nucleus accumbens.
What is the pain pathway affected by opioids?
Pain binds to nociceptors → dorsal horn → spinothalamic tract → thalamus → somatosensory cortex/limbic system.
Opioids block this at the spinal cord level.
How do opioids alter pain transmission in the spinal cord?
They reduce glutamate and substance P release and inhibit pain afferent activity.
What neurotransmitters are released in mild vs. strong pain?
Mild pain: Glutamate; Strong pain: Substance P.
What types of adaptation occur with chronic opioid use?
Increased metabolic activity and altered potassium channels due to opioids’ inhibitory effects.
What are the four opioid receptor action classifications?
Pure agonists (e.g., fentanyl, morphine)
Partial agonists (e.g., buprenorphine)
Antagonists (e.g., naloxone)
Mixed agonist-antagonists (e.g., pentazocine)
What are the subjective effects of opioid agonists?
Rush: Rapid euphoria
High: Joy
Nod: Disinterest
Straight: Baseline between cravings
What does conditioned place preference (CPP) show in opioid studies?
Animals prefer locations associated with opioid administration, indicating reinforcement.
What are signs of opioid overdose?
Severe respiratory depression, weak pulse, bluish skin/lips.
What causes respiratory depression in opioid overdose?
Inhibitory effects in the medulla.
What are the types of opioid withdrawal treatment?
Long-term: Outpatient, milder symptoms
Short-term: Inpatient, moderate symptoms
Rapid: Requires antagonists, severe
Ultra-rapid: Requires anesthesia and antagonists, very severe
