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23 Cards in this Set
- Front
- Back
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Catecholamine actions on smooth muscle?
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Excitatory on blood vessels
Inhibitory on gut, bronchial, blood vessels supplying skeletal muscles |
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Catecholamine actions on the heart?
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Cardiac excitation (↑ frequency and ↑ contractile force)
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Catecholamine actions on metabolism?
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Glycogenolysis from liver and skeletal muscles
Release of free fatty acids from adipose tissue |
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Catecholamine actions on endocrine?
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Modulation of the secretion of insulin, renin, pituitary hormones
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Catecholamine actions on CNS?
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Wakefulness, appetite, respiratory stimulation, psychomotor activity
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What type of inhibitors are most α receptor antagonists? What's the exception?
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Competitive
Phenoxybenzamine |
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What do α2-Adrenergic Receptors cause in the CNS?
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Limit sympathetic outflow
↑ vagal tone = ↑ parasympathetic outflow |
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What do α2-Adrenergic Receptors cause in the periphery?
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↑ platelet aggregation
↓ release of NE and ACh from nerve endings |
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How do α2-Adrenergic Receptors regulate metabolic activity? What's the most important regulator of this?
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↓insulin release = ↓fat synthesis and storage
↓lipolysis (due to direct effect on adipose tissue receptors) Plasma glucose level |
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What mediates the major response of clinical relevance for α-Receptor Antagonists?
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α1-receptors in smooth muscle cells
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What's the effect of alpha1 blockage at the blood vessels?
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↓ BP: (esp for standing pt)
Compensated by baroreflex = ↑ HR and CO |
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What exaggerates the baroreflex response in alpha blockers?
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If the antagonist also blocks α2 receptors NE is released, which activates β1 receptors
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What is the effect of administering α1-Adrenergic receptor antagonists after giving phenylephrine?
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Effects will be blocked completely
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What is the effect of administering α1-Adrenergic receptor antagonists after giving NE?
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β1-responses will remain
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What is the effect of administering α1-Adrenergic receptor antagonists after giving epinephrine?
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Vasopressor response may be converted into a vasodilator response due to β2-responses remaining intact
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What's the effect of α2 Receptor Antagonists in the periphery?
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↑ NE release by suppressing presynaptic α2 receptors
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What's the effects of α2 Receptor Antagonists in the CNS?
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↑ sympathetic outflow by augmenting the NE release which will increase by stimulation both α1 and β1 receptors in the periphery = ↑ BP
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What's an example of a β-Haloethylamines alkylating agent?
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Phenoxybenzamine
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What's an example of a Imidazoline analogue?
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Phentolamine
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What's an example of a Piperazinyl quinazoline?
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Prazosin
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What's an example of a Benzenesulfonamide?
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Tamsulasin
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What's an example of an Indole derivative?
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Yohimbine
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What's a Pheochromocytoma?
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Tumors of the adrenal medulla and adrenergic neurons → secretion of enormous quantities of catecholamines → severe hypertension
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