Term
| Presynaptic inhibition (CNS,PNS)? |
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Definition
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Term
| Inhibition of platelet aggregation? |
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Definition
|
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Term
| Types of purine receptors? |
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Definition
|
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Term
| Gi-couple purine receptors? |
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Definition
| A1, A3, P2Y12,P2Y13,P2Y14 |
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Term
| Gq-coupled GPCR activation effect? |
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Definition
| Increase in Phospholipase C |
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Term
| P2X receptors bind what purine over all others? |
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Definition
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Term
| Nucleoside vs. Nucleotide? |
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Definition
| Nucleoside = dephosphorylated (e.g. adenosine; Nucleotide = phosphorylated (e.g. AMP, ADP, ATP) |
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Term
| Which purine receptors are GPCRs and which are cation channels? |
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Definition
| GPCR = P1 (A), P2Y; Cation channel = P2X |
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Term
| Main neuronal P2X receptors? |
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Definition
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Term
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Definition
| Neurons; Astrocytes; Aggregating platelets; Damaged cells |
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Term
| Adenosine acting via A2A receptors has what effects? |
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Definition
| Vasodilation; Inhibition of platelet aggregation; Inhibition of immune cell activation; Postsynaptic stimulation in PNS/CNS; Stimulation of sensory nerves |
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Term
| Adenosine acting via A1 receptors has what effects? |
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Definition
| Contraction of some smooth muscle (e.g. renal blood vessels - decreases work demand); Inhibitory effects in heart (decreases force/rate); Preconditioning; Presynaptic inhibition in PNS/CNS |
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Term
| Which adenosine receptor is resistant to methylxanthines (e.g. caffeine)? |
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Definition
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Term
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Definition
| Short repeated periods of hypoxia (low oxygen) or ischemia (low blood supply) protect against later, prolonged hypoxia/ischemia |
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Term
| Receptors important in preconditioning? |
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Definition
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Term
| What happens if P2X7 receptors are overstimulated? |
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Definition
| Cell permeabilisation, cell death |
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Term
| How might adenosine-related drugs help Parkinson's Disease? |
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Definition
| Parkinson's = neurodegeneration of dopaminergic neurons in striatum. A2A receptors act antagonistically with D2 receptors (A2A activation inhibits D2). A2A antagonists therefore enhance the effects of D2 agonists. |
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Term
| How might adenosine-related drugs help in neuroprotection? |
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Definition
| A1 agonists are neuroprotective because they inhibit glutamate release (presynaptic inhibition; A2A receptor activation stimulates glutamate release (postsynaptic stimulation). A2A antagonists are neuroprotective. A2X7 antagonist may be neuroprotective. |
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Term
| How might adenosine-related drugs help in control of pain? |
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Definition
| A1 receptor activation in spinal cord = analgesic; A2A receptors are pronociceptive (increase pain); Systemic adenosine/A1 agonist = relief in chronic pain; Systemic adenosine/ATP used in surgery. |
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Term
| What is the effect of adenosine on sleep? How might adenosine-based drugs affect sleep? |
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Definition
| Adenosine = sedative (build-up during wakefulness); adenosine antagonists inhibit sleep (e.g. caffeine via A2A receptors) |
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Term
| Effect of P2X1 activation? |
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Definition
| Smooth muscle contraction (e.g. blood vessels) |
|
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Term
| Effect of P2Y1 activation? |
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Definition
| Smooth muscle relaxation; platelet aggregation (along with P2Y12) |
|
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Term
| Which receptors cause smooth muscle relaxation? |
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Definition
|
|
Term
| Which receptors cause smooth muscle contraction? |
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Definition
| A1 (e.g. renal), P2X1 (e.g. blood vessels) |
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Term
| How does ATP act on sensory nerves? |
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Definition
| ATP acts on P2X2/3 = excitation; ATP broken down to adenosine; Adenosine acts on A1 receptors = inhibition; Adenosine acts on A2A receptors = excitation |
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Term
| Which receptors cause platelet aggregation? |
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Definition
| P2Y1 (PLC activation, increased Ca2+), P2Y12 (decreased AC = enhanced aggregation) and P2X1 (increased Ca2+) |
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Term
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Definition
| Promotion of fluid release, especially from respiratory epithelium (cystic fibrosis, COPD, dry eye disease) |
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Term
| Effects of P2X3 antagonist? |
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Definition
| Analgesic (P2X3 activation on sensory nerve = pain), Incontinence (activation = bladder hyperactivity/hypersensitivity); IBS (activation = colon hypersensitivy and pain) |
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Term
| Effects of P2X1 antagonist? |
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Definition
| Vasodilator? Antispasmodic, Incontinence, Contraceptive (activation = smooth muscle contraction, antagonist prevents contraction), Antithrombotic (activation = platelet aggregation) |
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Term
| Effects of P2X4 antagonist? |
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Definition
| Chronic pain relief (P2X4 implicated along with and P2X7 in chronic pain)? |
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Term
| Effect of P2X7 antagonist? |
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Definition
| Anti-inflammatory? Chronic pain relief? Neuroprotective (P2X7 activation in microglia can cause neurodegeneration)? Reduced bone formation (antagonist may worsen osteoporosis?) |
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