Receptors Flashcards
Ion channels / Ligand-gated ion channel receptors
once the drug binds to a receptor on this target the channel is either opened or closed dependent
Lidocaine
G-protein coupled receptors (GPCRs)
When the drug binds to the target, it causes a sequence of events within the G-protein subunits
which then leads to production of a secondary messenger SUCH AS CYCLIC AMP OR A PROTEIN PHOSPHORYLATION CASCADE.
These second messengers are actually responsible for causing the effect.
Adrenoreceptors
Tyrosine kinase receptors
drug activates a tyrosine kinase receptor
leads to a series of steps within the cell, normally involving PHOSPHORYLATION OF TARGETS, then causing effects which often include cell growth and differentiation.
Insulin eg nsulin-like growth factor (IGF), epidermal growth factor (EGF)
Nuclear receptors?
located within the nucleus of the cell and activation or inhibition of these receptors typically causes increased or decreased gene transcriptio
Commonly used drugs that work via this route are steroids such as prednisolone and other hormone replacements such as levothyroxine
eg of Ligand-gated ion channel receptors
mediate fast responses
e.g. nicotinic acetylcholine,
GABA-A &
GABA-C, glutamate receptors
non-receptor tyrosine kinase?
Prolactin, Immunomodulators (cytokines IL-2, Il-6, IFN), GH, G-CSF, Erythropoietin and Thromobopoietin
Guanylate cyclase receptors
contain intrinsic enzyme activity
e.g. atrial natriuretic factor, brain natriuretic peptide
Gs receptor does what
Stimulates adenylate cyclase → increases cAMP
Beta-1 receptors (epinephrine, norepinephrine, dobutamine)
H2 receptors (histamine)
Gi receptor dies what ?
Inhibits adenylate cyclase → decreases cAMP
M2 receptors (acetylcholine)
Gq receptor does what ?
Activates phospholipase C
Alpha-1 receptors (epinephrine, norepinephrine)
