Study Set Content:
21- Flashcard


• Alpha (0)-0,0

• Beta (B)-B: B,B

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22- Flashcard

are coupled via G proteins in the Gq family to phospholipase C.

Alpha 1 receptor

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23- Flashcard

This enzyme hydrolyzes (blank)

leading to the formation of (blank) and (blank). IP, promotes the release of sequestered (blank) from intracellular stores, which increases the cytoplasmic concentration of free(blank) and the activation of various calcium-dependent protein kinases

polyphosphoinositides, inositol 1,4,5 trisphosphates (IP,), diacylglycerol (DAG), Ca 2+

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24- Flashcard

Activation of these receptors may also increase____ across the cell's plasma membrane

influx of calcium

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25- Flashcard

inhibit adenylyl cyclase activity and cause intracellular cyclic adenosine monophosphate (CAMP) levels to decrease.

Alpha 2 receptors

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26- Flashcard

Alpha 2 -receptor-mediated inhibition of adenylyl cyclase activity is transduced by the inhibitory regulatory protein, (blank). It is likely that not only a, but also the B-y subunits of Gi contribute to inhibition of adenylyl cyclase.


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27- Flashcard

Activation of all three receptor subtypes: ____results in stimulation of adenylyl cyclase and increased conversion of adenosine triphosphate (ATP) to CAMP

(B1, B2, and B.)

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28- Flashcard

In the heart B-receptor-activated CAMP synthesis (blank) the reflux of calcium across the cell membrane and its sequestration inside the cell.


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29- Flashcard

Activation of the cyclase enzyme is mediated by the

stimulatory coupling protein Gs.

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30- Flashcard

is the major second messenger of B-receptor activation.

Cyclic AMP

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31- Flashcard

Beta-receptor activation also promotes the

relaxation of smooth muscle

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32- Flashcard

Beta adrenoreceptors may activate ____ in the heart via Gs-mediated enhancement independently by changes in CAMP concentration

voltage-sensitive calcium channels

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33- Flashcard

is a low affinity receptor compared with B, and B2 receptors but is more resistant to desensitization.

B, adrenoreceptor

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34- Flashcard

The D1 receptor is typically associated with the

stimulation of adenylyl cyclase

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35- Flashcard

have been found to inhibit adenylyl. Cyclase activity, open potassium channels and decrease calcium influx.

D2 receptors

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36- Flashcard

Responses mediated by adrenoceptors are not

fixed and static.

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37- Flashcard

The number and function of adrenoceptors on the cell surface and their responses may be regulated by (blank) themselves, other hormones and drugs, age, and a number of disease states.


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38- Flashcard

One of the best-studied examples of receptor regulation is the ____ that may occur after exposure to catecholamines and other sympathomimetic drugs.

desensitization of adrenoceptors

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39- Flashcard

After a cell or tissue has been exposed for a period of time to an

agonist, that tissue often becomes____ to further stimulation by that agent.

less responsive

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40- Flashcard

Other terms such as ____ have also been used to denote desensitization.

tolerance, refractoriness, and tachyphylaxis

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