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24 Cards in this Set
- Front
- Back
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Nicotine |
-nicotine effects dissipate in a few minutes, causing need for repeated smoking -repeated exposure means nicotine receptors undergo changes (desensitisation and up regulation), more needed to produce desirable effects Up regulation; body is still making receptors, more smoke needed |
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Effects of Aspartate on CNS |
-NMDA binds to Aspartate (looks same as glutamate) -activates NMDA receptors, makes amino acids -it is an excitatory neurotransmitter |
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How glutamate acts to increase free intracellular Ca2+ levels |
-binds to AMPA receptor -allows Na+ in -triggers depolarisation response -blocks magnesium -allows Ca2+ influx |
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Cascade of adrenaline binding to its receptor and allowing ca2+ influx |
Adrenaline-> activates adenyl Cyclase-> turns ATP to CAMP -> activates protein kinase A-> + glycogenolysis and -gluconeogenesis |
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3 examples of drugs that work via G-protein coupled receptors |
-Antihistamines -antipsychotics -antidepressants
SPECIFICALLY: -salbutamol -pantoprazole -adrenaline |
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A rise in calcium triggers a number of events in the cell |
-binds to regulatory proteins/troponin= muscle contraction -activates K+ channel found in nerve cells -signal transduction -coagulation |
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What is the half life on insulin |
-4-6 mins -determined by the enzyme which breaks it down |
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What is the half life of the insulin receptor |
-6-7 hours -determined by synthesis degredation/activation |
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Structure of the insulin receptor |
-inactive: monomer, alpha and beta subunits linked by disulphides bond -active: dimer, 2 alpha 2 beta subunits |
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Insulin and Tyrosine Kinase receptor |
-insulin receptor: momomer -dimerises (activated) -Insulin activates TK receptor -TK transfers phosphate group from ATP -autophosphorylation of tyrosine residue of cytoplasmic protein in beta subunit -stimulates insulin receptor substrates -activates protein kinase A -exocytoxins of glut-4 containing vesicles bring glucose to cell -causes metabolic response -effects triggered in cytoplasm or nucleus depending on cell |
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Bifunctional enzyme |
-enzyme containing 2 diff catalytic sites -can be inactive/active or both active -ie. Can make and break down glycogen at same time |
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Phosphorylated form of enzyme |
-turns enzyme on or off -phosphorylation= excess ATP -whole pathway is phosphorylated -drives 1 pathway and stops another |
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Receptor signalling speeds |
G protein: seconds Insulin: minutes-hours |
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Receptor signal propagation mechanism |
G protein: -binds to G protein couples (alpha, beta or gamma) -alpha dissociates and interacts with receptor -cascade of events by cAMP or Ca2+ Insulin: -dimerises, ligand binds -autophosphorylation of tyrosine residues -phosphorylation of IRS -cascade phosphorylated proteins -cellular nucleus responses |
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G protein Receptors |
-Adrenoreceptors -mACHR -GabaB RESPONSE IN SECONDS |
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G protein Receptors |
-Adrenoreceptors -mACHR -GabaB RESPONSE IN SECONDS |
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Ligand Gated Receptors |
-nACHR -GabaA Response in milliseconds |
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G protein Receptors |
-Adrenoreceptors -mACHR -GabaB RESPONSE IN SECONDS |
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Ligand Gated Receptors |
-nACHR -GabaA Response in milliseconds |
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Enzyme linked receptors |
-tyrosine kinase -guanylyl cyclase Response in minutes to hours |
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G protein Receptors |
-Adrenoreceptors -mACHR -GabaB RESPONSE IN SECONDS |
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Ligand Gated Receptors |
-nACHR -GabaA Response in milliseconds |
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Enzyme linked receptors |
-tyrosine kinase -guanylyl cyclase Response in minutes to hours |
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Nuclear receptors |
-oestrogen receptor -testosterone receptor Response in hours |
