Pharma 1 Flashcards
Name 2 clinically used agonists:
Adrenaline: increase heart rate and force, anaphalactic shock
Morphine: severe pain analgesic
Name 3 clinically used antagonists:
Naloxone: opiate receptor, opiate overdose
Atropine: muscarinic receptor, eye drops
Beta blockers: Beta adrenoceptors, hypertension and anxiety
What is the lipid theory?
GAs dissolve in membrane leading to:
Changes in bilayer thickness
Changes in order parameters
Changes in curvature elasticity
What are the problems with the lipid theory?
The cut off effect
Stereoisomers
Temperature has the same effect but no anaesthesia
New compounds do not fit the Meyer-Overton correlation
What is the protein theory?
GAs bind to specific membrane proteins:
GABAa receptors
2 pore potassium ion channels
NMDA receptor
What are the criteria for relevant anaesthetic targets?
- Reversably alters target function at clinically relevant concentrations
- Target expressed in appropriate anatomical location in brain/spinal cord
- Stereo selective effects in vivo parallel actions on the target in vitro
- Target exhibits appropriate sensitivity/insensitivity to model and non-anaesthetic compounds
Why does greater solubility in the blood lead to inhaled anaesthetics being less effective?
Greater solubility in blood
Lower rate of rise of alveolar partial pressure
Lower rate of rise of brain partial pressure
Slower rate of onset of anaesthesia
Name 2 IV anaesthetics:
Propofol -Patient wakes up after 5-10 minutes Thiopental -Conscious returns in 10-20 minutes Both potentiate GABAa receptors and have a high lipophilicity
Name 3 inhalation anaesthetics:
Halothane -potent but causes severe hepatotoxicity Isoflourane -Fall in BP -Depress respiration and muscle relaxant Nitric Oxide -Maintainance of anaesthesia and analgesia -50-66% with oxygen
Two main components of pain pathways:
Peripheral nociceptive afferent neurons
Central
What are the two peripheral pain pathways:
Fast pain -Adelta fibres -Myelinated -1-5 micrometre diameter -Fast conductance Slow pain -C fibres -Unmyelinated -0.1-1.5 micrometre diameter -slow conductance
What is the gate theory?
Non-painful input (distractive input) closes the “gates” to painful input preventing pain from travelling to the CNS
What are the CNS effects of Opiods?
Profound analgesia Respiratory depression Nausea and vomiting Eurphoria Dry mouth Drowsiness Depression of cough reflex Pupillary constriction
What is morphine used for clinically?
Used for acute+chronic pain
Injected, rectal or oral
3-4 hour half life
Name three GPCR receptors:
Dopamine
Opioid
Ach
