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17 Cards in this Set
- Front
- Back
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First intracellular signal molecule to be discovered?
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Cyclic AMP
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Intracellular molecule involved in blood dilation & sight.
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Cyclic GMP
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The size/strength of signal transduction depends on what?
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The fraction of total membrane receptors occupied by the ligand
-Concentration of Hormone to receptor complexes. therefore depends on affinity |
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Kd defined as what & equation?
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Concentration by which 50% of the binding sites are occupied by ligands.
Kd = [H] x [R]/ [HR] |
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Affinity defined as what in terms of Kd?
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Affinity = 1/Kd
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How much of the genome encodes receptors?
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5%
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How much prescription med target receptors?
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40%
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Neurotransmitters are an example of what?
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Paracrine
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Ion channel receptors activated when?
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Ligand binds
Cell potential (diff in electrical charge on either side of the membrane) |
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Speed of ion channels?
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Milliseconds
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2 Examples of ion channels?
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GABAa for GABA
Nicotinic for Ach |
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Nicotinic receptor antagonist?
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Tubocuarine - on skeletal muscle cells
-used in surgery for relaxation Actions reversed by increasing Ach by decreasing acetylchlorinesterase which destroys Ach. |
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GAMAa receptor function & drugs?
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Opens cl- channel causing hyperpolarisation & cell inhibition.
Tranqulisers & Anticonvulsants |
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How long do GCPR take?
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Seconds to minutes
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The 3 families of G proteins and what they activate?
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Gs - Stimulate Adenylate cyclase -->PKA
Gi - inhibits adenylate cyclase Gq - Activates phosphpolipase C --> DAG + IP3 IP3 --> Ca2 Ca2 ->PKC + DAG [activation of PKC] |
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Prazosin
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competitive reversible antagonist at a1 adrenoceptor
-->Dilation of blood vessels --> fall in BP |
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What receptor is starting to become a major drug target?
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Tyrosine kinases
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