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Flashcards in deck_662781 Deck (19):
1

At what part of teh cell does signal transduction tend to take place?

At the edge of the cell

2

What does adenylyl cycles cause the conversion of?What does this effector do?

ATP to cAMP-- uses ~1% of cells ATP concentrationcAMP causes the action of cAMP dependent protein kinase (PKA)-- binding of cAMP to regulatory subunits activates catalytic subunits which phosphorylate target proteins in the cell

3

What does phospholipase C cause the conversion of?

PIP2 to IP3 and DAG

4

What does phosphonositide 3-kinase cause the conversion of?

PIP2 to PIP3

5

What does cGMP phosphodiesterase cause the conversion of?

Cyclic GMP to 5'GMP

6

Which receptors have an effect on adenylyl cyclase?

Gs-coupled receptors-- β-adrenoceptors-- D1 dopamine receptors -- H2 histamine receptorsGi coupled receptors-- α2-adrenoceptors-- D2 dopamine receptors -- μ-opioid receptors

7

What receptors have an effect on phospholipase C?

Gq-coupled receptors-- α1-adrenoceptors-- M1 muscarinic receptors -- H1 histamine receptors

8

How are signals amplified?

The enzyme in the reactions causes a multiple product molecules, which causes the amplification

9

Describe the action of phospholipase C

Catalyses the cleavage of PIP2 into IP3 and DAG1. Agonist binds and causes a conformational change2. GTP for GDP eachange takes place3. Alpha-q GTP activates PLC4. PLC cleaves PIP2 to IP3 and DAG

10

What does IP3 cause?

Opens IP3 receptorcauses Ca2+ to flow into cytoplasm from SR/ER

11

Describe positive ionotropy in the heart

Adrenaline in the blood and noradrenaline bind to B1 adrenoceptors in the ventricular walls --> releases cAMP --> activates PKA --> phosphorylates and activates VOCC --> increase [Ca] --> Ca induced Ca releaseALSO -- alpha-s GTP directly interacts with VOCCs

12

Describe arteriolar vasoconstriction

Noradrenaline binds to alpha1 adrenoceptors, stimulating phopholipase C-- generates InsP3 (releases ER Ca2+) giving a contractile response-- DAG activates protein kinase which phosphorylates target proteins to maintain the vasoconstriction

13

The action of what hormone causes venoconstriction on which receptors?

noradrenaline acts on alpha1 adrenoceptors to cause venoconstriction

14

The action of what hormone causes bronchoconstriction on which receptors?

Parasympathetic ACh acts on M3 muscarinic receptors

15

Where else can smooth muscle be contracted?

GI tract and genitio-urinary smooth muscle

16

Though which effector does smooth muscle contraction come about?

Gq phospholipase C to IP3 (Ca2+) and DAG (PKC)-- Increasing [CA] will increase contractility

17

What regulates neurotransmitter release?

presynaptic G protein- coupled receptors are regulators in both the PNS and CNS

18

How is neurotransmitter release regulated?

G-beta/gamma subunits inhibit specific types of VOCCs reducing Ca2+-influx which limits neurotransmitter release

19

What receptors are involved in neurotransmitter release?

μ-opioid receptors