Term
| What is histamine synthesized from? (Precursor and enzyme) |
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Definition
| Histidine and histidine decarboxylase |
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Term
| What are the normal physiological functions of histamine? |
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Definition
| Growth and regeneration, neurotransmitter, regulates microcirculation |
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Term
| What type of injury causes histamine release? |
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Definition
- Inflammatory response
- Mechanical, thermal, radiant
- Chemical injury (venom, morphine)
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Term
| Where is histamine stored? |
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Definition
| Mast cells and blood basophils |
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Term
| What are the downstream effects of histamine? |
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Definition
Vascular: arterial constriction, terminal vessel dilation, increased vascular permeability
PNS: sensory neuron stimulation to cause itching and pain
CNS: wakefulness, nausea
Smooth Muscle: bronchiolar and intestinal smooth muscle constriction
Muscarinic: increased mucous secretion in lungs, stomach, and mouth |
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Term
| What is the mechanism of action of H1 antihistamines? |
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Definition
| Inverse agonists of H1 receptors |
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Term
| What are the effects of H1 antihistamines? |
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Definition
- Sedative
- Anti-nausea
- Can be excitatory in young children
- Drying of mucous membranes
- Anesthetic
- Relaxes bronchial smooth muscle
- Anti-allergy
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Term
| Why do H1 antihistamines dry out mucous membranes? |
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Definition
| They block muscarinic cholinergic receptors |
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Term
| Why does H1 antihistamine act as an anesthetic? |
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Definition
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Term
| What are therapeutic indications for H1 Antihistamines? |
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Definition
| Allergic responses, anti-emetics, sedatives |
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Term
| Which generation of H1 blockers can enter the CNS? |
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Definition
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Term
| What are the first generation H1 blockers? |
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Definition
| Diphenhydramine, Clemastine, Chlorpheniramine, Hydroxyzine, Promethazine, Tripelennamine |
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Term
| What first generation H1 blocker is commonly used as a sedative? |
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Definition
| Diphenhydramine (Benadryl) |
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Term
| Which first class H1 blockers are commonly used as anti-emetics? |
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Definition
| Hydroxyzine and promethazine |
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Term
| Which H1 blockers cannot enter the CNS? |
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Definition
| Loradatine, Fexofenadine, Desloratadine, and Cetirizine |
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Term
| Side effects of H1 antihistamines? |
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Definition
| Can interact with alcohol, possible allergic response, dry mouth/blurred vision/constipation |
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Term
| What are the downstream effects of H2 blockers? |
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Definition
| Decrease hydrogen ion secretion from parietal cells of the stomach |
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Term
| What are the H2 blockers? |
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Definition
| Cimetidine, Ranitidine, Famotidine, Nizatidine |
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Term
| What is the enzyme pathway for synthesis of serotonin? |
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Definition
| Tryptophan --(tryptophan hydroxylase) --> 5-hydroxytryptophan--(aromatic aminoacid decarboxylase)--> 5-OH tryptamine (5HT) |
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Term
| What are the physiological functions of serotonin? |
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Definition
1. Smooth muscle constriction
2. Activates sensory neurons
3. CNS neurotransmitter
4. Induces nausea in CNS |
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Term
| Where is serotonin found? |
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Definition
| Enterochromaffin cells in the gut and in platelets |
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Term
| What is carcinoid syndrome? Symptoms? |
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Definition
| Non-malignant tumor of enterochromaffin cells that leads to an overproduction of serotonin. Causes diarrhea and cramping, bronchospasm, skin flushing, and pellegra |
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Term
| What condition did Dr. Fertel mention that are treated with serotonin agonists? How do they help? |
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Definition
| Migraine headaches. Migraines are caused by dilation of blood vessels in the head, and serotonin agonists cause blood vessel constriction. |
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Term
| What are the 5HT1 agonists? |
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Definition
| Sumatriptan, other "triptans", and ergot alkaloids (ergotamine, dihydroergotamine) |
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Term
| What are the effects of Sumatriptan? |
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Definition
| Cause CNS vasoconstriction, decrease peptide neurotransmitters |
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Term
| What is ergotism and how is it caused? |
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Definition
| Consumption of ergot alkaloids from moldy bread. Causes severe vasospasms that lead to gangrene |
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Term
| What are the side effects of the ergot alkaloids? |
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Definition
- Life-threatening vasospasms
- Can have LSD-like effect on the CNS
- Can cause uterine contractions (category X)
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