General Adrenergic Receptors Flashcards Preview

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Flashcards in General Adrenergic Receptors Deck (13):
1

Which type of adrenergic receptor is a G-alpha-q receptor?

Alpha 1

2

What kind of signal is sent by the alpha-1 g-alpha-q receptor?

An excitatory signal to the blood vessels.

3

What second messengers are activated by the g-alpha-q receptor and what does this result in?

Phospholipase C (PLC) is activated which hydrolyzes phosphoinositol (PIP2) into IP3 and DAG. IP3 causes an increased release of intracellular calcium and DAG activates protein kinase C which causes the phosphorylation of proteins causing them to be activated.

4

What type of a physiologic response results from activation of the alpha-1 g-alpha-q receptor?

Smooth muscle constriction.

5

Which type of adrenergic receptor is a g-alpha-i receptor?

Alpha-2

6

What kind of signal is sent by the alpha-2 g-alpha-ireceptor?

Inhibitory.

7

To which three places do the alpha-2 q-alpha-i receptors send inhibitory signals?

1. Brain
2. Blood vessel
3. Pre-synaptic on the post ganglionic neuron innervating the blood vessels.

8

What second messengers are inactivated by the alpha-2 g-alpha-i receptors?

Adenylate cyclase is inactivated so ATP cannot be converted into cAMP. So we have a decrease in cAMP and potassium conductance is increased.

9

What type of physiologic responses result from activation of the alpha 2 g-alpha-i receptor?

Smooth vessels constrict (cAMP is responsible for smooth muscle relaxation). Potassium conductance is increased and the cell is hyperpolarized.

10

What types of adrenergic receptors are g-alpha-s receptor?

Beta 1, 2 & 3.

11

What kind of signal is sent by the beta 1, 2 & 3 g-alpha-s receptors?

It could be excitatory or inhibitory depending on cAMP actions.

12

What second messenger is activated by the beta 1, 2 & 3 g-alpha-s receptors?

The activation of adenylate cyclase is responsible for converting ATP into cAMP.

13

What types of physiologic responses result from the activation of beta 1, 2 & 3 g-alpha-s receptors?

The increase in cAMP relaxes smooth muscle, increases the force of contraction of the heart and increases the rate.