C. Opioid Tolerance 1 Flashcards
Describe the differences between opium, opiate and opioid.
Opium is the extract of the juice of the oriental poppy.
Opiate is derived from the opium poppy. a drug with a morphine-like structure
Opioid is a drug with a morphine like action (acts on opioid receptors
What are the three types of G protein-coupled receptors ?
Where are they expressed
Mu, MOP- spinal chord, periphery and brain
Kappa, KOP- mainly periphery after inflammation
Delta, DOP- spine
Name the endogenous opioid peptides and where they act on the body and what receptor they act on
Enkephalins- CNS and in immune cells Meu and Delta
Endorphins- brain meu
dynorphins- CNS Kappa
Endomorphins- Meu more potent
How can a meu receptor be targeted and how does that lead to the reduction of neurotransmitters?
- Inhibition of adenylyl cyclase, reducing cAMP
- Activation of potassium channels, hyperpolarising the neuronal membrane
- Inhibition of calcium channels, reducing calcium influx, inhibiting neurotransmitter release
2 and 3 lead to reduction of neurotransmitter release. through manipulating ion channels
Name 3 morphine analogues
Codeine
Diamorphine (heroin)
Naloxone (antagonist)
Name 4 synthetic opioids
Pethidine
Fentanyl
Methadone
Pentazocine
What is an opioid ligand that is peripherally-acting and used as treatment of diarrhoea
Loperamide
What are some properties that opioids have?
Analgesia
Euphoria
Respiratory depression
Cough suppression (anti-tussive)
Nausea and vomiting
Pupillary constriction
Inhibition of gastrointestinal tone and motility causing constipation
Histamine release from mast cells
What are the desirable effects of opioid agonists?
Analgesia
Anti-diarrhoea
Anti-tussive
What are the non-medical effects of opioid agonists?
Rush (euphoria)
Prolonged sense of contentment and well-being
Undesirable
Respiratory depression and low co2 Nausea and vomiting Dizziness and confusion Pupilloconstriction Constipation Addictive Tolerance Pruritis Death due to overdose
