Cell Signaling Flashcards

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1
Q

Paracrine Signaling

A

a form of signaling where a cell produces a signal to induce changes in nearby cells

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2
Q

properties of Paracrine agents

A

rapidly degraded, only effects local tissue, does not enter the blood stream

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3
Q

Autocrine signaling

A

a form of signaling where a cell secretes a hormone or chemical messenger that binds to the same cell to induce changes in the same cell

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4
Q

properties of Autocrine agents

A

action on the same cell that secreted them

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5
Q

responses of Autocrine agents are mediated by receptors in the

A

membrane, cytoplasm, and nucleus

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6
Q

Eicosanoids

A

locally acting fatty acid hormones, made from arachidonic acid, located in the plasma membrane

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7
Q

Eicosanoids examples

A

Prostaglandin
Thromboxane
Leukotrienes

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8
Q

Phospholipase A2

A

converts phospholipid to Arachidonic acid
inhibited by Glucocorticoids

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9
Q

Cyclooxygenase

A

converts arachidonic acid to Endoperoxides
inhibited by Aspirin and NSAIDs

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10
Q

Subtypes of Cyclooxygenase

A

COX 1 - platelet aggregation pathway, protects stomach
COX 2 - pain and inflammation pathway
COX 3 - fever link? (recently discovered)

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11
Q

Prostacyclin Synthase (PGI2, prostaglandin I2)

A

vasodilator, bronchodilator, decreased platelet aggregation

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12
Q

Thromboxane Synthetase (TxA2)

A

vasoconstrictor, bronchoconstrictor, increased platelet aggregation

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13
Q

Leukotrienes

A

involved in asthmatic and allergic reactions, stimulated T cells, interleukin, interferon production, bronchoconstriction, increased vascular permeability

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14
Q

Action of NSAIDs and Aspirin

A

inhibits Cyclooxygenase

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15
Q

Aspirins

A

anticlotting pathways, can lead to ulcers

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16
Q

Ibuprofens

A

inhibit inflammatory reaction in pathway (PGI2) inhibits COX 1 & 2

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17
Q

Naproxen (Aleve)

A

similar action to ibuprofen

18
Q

Indomethacin

A

removed pain and swelling (arthritis)

19
Q

Cox 2 inhibitors

A

inhibits pain/inflammation pathway without altering clotting,

20
Q

High doses of ibuprofen for 18 months doubles heart attack chance

A

True

21
Q

Acetaminophens

A

analgesic, antipyretic, may inhibit COX 3 pathways

22
Q

New anti-asthmatic/anti-allergy medications

A

block leukotriene pathways

23
Q

Signal Transduction

A

Signal = receptor activation
Transduction = stimulus transformed into a response

24
Q

Lipid Soluble messages

A

steroid hormones
intercellular receptors
regulate gene transcription

25
Q

Lipid Insoluble messages

A

utilize plasma membrane receptors
several models of action

26
Q

First Messenger Systems

A
  1. Receptor Coupled with Ion Channel
  2. Receptor Coupled with Protein Kinase
27
Q

Receptor Coupled with Ion Channel

A

messenger binds to receptor
receptor activated gated ion channel

28
Q

Receptor Coupled with Protein Kinase

A

messenger binds to receptor
receptor binds to Tyrosine Kinase which Phosphorylates Protein
mediates cell response in growth and development

29
Q

Second Messenger Systems

A

activate G proteins
cAMP, IP3, DAG, Ca++
1st messenger - receptor - G Protein - Effector Protein - 2nd Messenger, G Protein couples receptor and effector

30
Q

Cyclic AMP (cAMP)

A

second messenger, Adenyl Cyclase is the Effector, activates protein kinases, phosphorylates proteins (inhibit or stimulate)

31
Q

phosphodiesterase

A

degrades cAMP into 5” AMP, blocking this with caffeine augments cAMP and Guanylyl Cyclase Analog (cGMP) effects

32
Q

Guanylyl Cyclase Analog (cGMP)

A

responsible for vision

33
Q

IP3, DAG

A

second messengers, Phospholipase C is the Effector, PIP2 converted into IP3+ DAG

34
Q

DAG

A

activates protein kinases, phosphorylating proteins, mediates cell responses

35
Q

IP3

A

makes ER membranes leaky to Ca++, increases cytosol Ca++, mediates cell responses

36
Q

Intracellular Ca++ is increased by

A

G Proteins activating membrane Ca++ gates,
IP3 mediating the release of Ca++ from the ER,
active transport of Ca++ out is blocked by a 2nd messenger,
opening of voltage gated channels

37
Q

Calcium MoA

A
  1. Ca++ bind to Calmodulin (changes protein shape, activation or inhibition)
  2. Ca++ binding to enzymes
  3. Ca++ binding to proteins (alters conformation and reactions)
  4. Ca++ mediates neurotransmitter release
38
Q

caffeine

A

worlds most widely consumed psychoactive drug, 90% of adults each day use caffiene

39
Q

caffeine Methylxanthine

A

coffee, tea

40
Q

caffeine Theobromine and Theophylline

A

chocolate and tea
Theobromine family = vasodilators for the brain

41
Q

caffeine MoA

A

blocks Adenosine receptors, inhibits Acetylcholinesterase, Blocks phosphodiesterase (increases cAMP), stimulates neurotransmitters(ACh, E, NE, DOPA, Sero)

42
Q

Adenosine

A

neuromodulating agent, downregulates CNS activity, can accumulate and trigger sleep