Codeine

Question 1

what is Codeine

Answer 1

An opiate receptor agonist in the CNS

Question 2

what is the Codeine’s analgesic activity is, most likely, due to

Answer 2

Conversion to morphine

Question 3

what is Codeines mechanism of action down to?

Answer 3

• Mediation of opiate receptors are coupled with G-protein receptors
• These activate adenylate cyclase and the production of cAMP

Question 4

how do opioids decrease intracellular CAMP?

Answer 4

by inhibiting adenylate cyclase

Question 5

what else happens when adenylate cyclase is inhibited?

Answer 5

The release of the nociceptive neurotransmitters
-Substance P
-GABA
-Dopamine
-Acetylcholine 
-Noradrenaline
As well as the hormones 
-Vasopressin
-Somatostatin
-insulin 
-Glucagon 
are inhibited

Question 6

how do hyperpolarization and reduced neuronal excitability arise from opioids?

Answer 6

• Opioids also close N-type voltage-operated calcium channels (OP2-receptor agonist)
• Open calcium-dependent inwardly rectifying potassium channels (OP3 and OP1 receptor agonist)