Opioid Receptors Flashcards
What are some endogenous opioids?
enkephalins, b-endorphins
How do opioid receptors affect the signalling pathway?
decreas Ac, increase K, decrease Ca, all Gi/o
what are the specific ligands for opioid receptors?
DAMGO
what are orphan GPCRs?
proteins that have similarities to the receptors whose ligands have not yet been identified
Which types of Ca channel are regulated by opioid receptors?
N, P and Q can be inhibited to regulate pain
Which G-protein subunit binds to the Ca channel?
Gbg
where are MOPRs found?
PAG/amygdala
how do MOPRs work in the reward pathway?
they disinhibit DA neurons by inhibiting GABA release in the ventral segmental area
what methods can we use to tell if morphine is addictive?
conditional place preference
self-administration
What do B arrestins 1 and 2 interact with?
b-adrenergic receptors
What are b-arrestins?
scaffolding proteins coupled to GPCRs that can bring signals to outer receptors and is involved in receptor endocytosis leading to tolerance
How do B-arrestins lead to endocytosis?
phosphorylation of the GPCR by GRK or a BARK complex stimulated by Gbg causes uncoupling of the ligand. recruitment of b-arrestin usually targets the receptor for endocytosis via clatharin coated vesicles
What are some of the side-effects of opioids?
analgesia, constipation, respiratory depression, cough reflex suppression, addiction and dependence, immunosuppression
What can be observed in a Barrestin2 KO?
reduced tolerance, increased basal analgesia, morphine is more rewarding and locomotion slows, respiratory depression, constipation and locomotion are all reduced
what synthesises DA?
tyrosine hydroxylase
