Analgesics

Question 1

What are the endogenous opioids called?

Answer 1

Enkephalins

Question 2

How do inhibitory interneurons help reduce pain?

Answer 2

Release enkephalins which reduces post-synaptic depolarisation and slows conduction of pain to the brain.

Question 3

NSAID’s reduce the production of what main eicosanoid that stimulates pain receptors?

Answer 3

Prostaglandins

Question 4

Prostaglandins and bradykinin activate what type of receptor?

Answer 4

GPCR

Question 5

What is cyclooxygenase-2?

Answer 5

Enzyme that converts Arachidonic acid to prostaglandins and thromboxane

Question 6

COX-2 selective NSAIDs have what unwanted side effect?

Answer 6

Increased risk of MI

Question 7

How does urinary alkalinisation work to treat Aspirin overdose?

Answer 7

Salicylic acid and salicylate exist in equilibrium in the body. Salicylic acid can be reabsorbed from the kidney, salicylate cannot and is excreted.

Le Chatelier’s principle means that decreasing protons (more alkaline environment) will increase salicylate which then stays in the kidneys and is excreted.

Question 8

Which GPCRs are activated by opioids? What effect does this have?

Answer 8

Gi, reduced cAMP, increased K+ influx, decreased membrane potential and release of neurotransmitters, less action potentials.

Question 9

Where do sensory signals travel to before synapsing?

Answer 9

Spinal cord

Question 10

How do local anaesthetics reduce pain?

Answer 10

Block sodium gated ion channels = no action potentials

Question 11

What is the danger of an accidental intravascular injection of lidocaine?

Answer 11

Blockage of sodium gated ion channels in other parts of the body, mainly cardiac, causing arrythmias or arrest

Question 12

What are the three broad types of pain?

Answer 12

Nociceptive, Neuropathic and Nociplastic