Flashcards in Pharmacodynamics Deck (77)
What are the four main locations that drugs act on?
2. On DNA
What drugs stimulate receptors?
What drugs prevent receptor stimulation?
What do receptors do?
They initiate cellular responses
What are receptors?
Proteins in or on cells?
What are the four main types of proteins that receptors are linked to?
1. G-protein coupled receptors
2. Ion channels
3. Gene transcription
Name a Beta2 adrenoceptor agonist
Name a Beta2 receptor antagonist
Name a H1+2 receptor agonist
Name an opiate Mu receptor agonist
Name an opiate Mu receptor antagonist
Name a M2 muscarinic agonist
Name a M2 muscarinic antagonist
How do G protein coupled receptors interact with ion channels?
They cause confirmation changes which allow ion exchange
How to G protein coupled receptors affect enzymes?
They activate or inhibit enzymes which will result in second messengers being produced or inhibited
What are the two types of opioid analgesics?
1 - Morphine based
2 - Synthetic
What are the three main opioid receptors?
Delta, Kappa and Mu
What type of receptors do opioids act on?
G-Protein Coupled Receptors
What occurs after receptor binding of opioids?
1. Inhibition of adenylate cyclise -> decreased intracellular cAMP
2. Couple to K:Ca ion channels -> inhibition of transmitter release and postsynapse excitability
75% of presynapse receptors for opioids are....?
By what 3 means do opioid analgesics work?
1. Inhibits pain transmission in dorsal horn
2. Activates descending pathways in grey matter inhibiting pain transmission (reduced GABA)
3. Inhibits nociceptive afferents in tissues
How is pain transmission inhibited at the dorsal horn?
By inhibiting presynaptic afferent impulses
How are the descending pathways activated?
By inhibiting GABA release in periaqueductual grey matter (PAG)
Why does activating the descending pathways inhibit pain?
It inhibits the discharge of the Dorsal Horn
What does the dorsal horn project into?
What does the thalamus project in to?
Why does respiratory depression occur when morphine is administered?
The activation of Mu receptors reduce the respiratory centres sensitivity to CO2
Why can nausea and vomiting occur when morphines administered?
Activation of the chemoreceptors trigger zone
Why can pupillary constriction occur when morphine is administered?
Activation of the kappa receptors leads to the stimulation of the oculomotor nucleus (parasympathetic NS)