signaling

Question 1

extracellular signals

Answer 1

1. Gases – cross membranes
   -NO smooth muscle relaxation
2. Hormones
   Cross membranes – bind to intracellular receptors
   Secreted and bind elsewhere
3. Other Ligands

Question 2

1. gases- NO- nitric acid

Answer 2

• freely soluble in tissue
• can cross membranes (connexin channels)
• Made from arginine by NO synthase

Question 3

acetylcholine

Answer 3

neurotransmitter causes activation of NO synthase

Question 4

heart pain

Answer 4

due to inadequate blood flow (angina)

Treat patients with nitroglycerine

Question 5

viagra

Answer 5

no phosphodiesterase

Question 6

smooth muscle relaxation

Answer 6

Brain – sends signal
Neurotransmitter binds to receptor (AChR)
Activates NOS to generate NO
NO crosses plasma membrane and activates guanylylcyclase to generate cGMP
cGMP causes smooth muscle relaxation
Phosphdiesterase cleaves cGMP to stop signal

Question 7

2. hormones

what type of hormones

Answer 7

Steroid hormones
Sex hormones (testosterone)
Thyroid hormones (thyroxine)

Question 8

hormones contin.

Answer 8

• Hydrophobic molecules
• Activate receptors to bind DNA and start transcription
• DHT and AR

Question 9

gpcr

G protein-coupled receptor

Answer 9

• Consists of receptor that binds ligand AND G-protein complex
• Characteristic structure (serpentine)
• 7-pass transmembrane receptor
• Trimeric GTP-binding protein (G protein)
• alpha, beta and gamma subunits

Question 10

ion linked channels

Answer 10

second messengers

Question 11

Gs

Answer 11

stimulatory G protein (increase cAMP)

Question 12

Gi

Answer 12

inhibitory G protein (decrease cAMP)

Question 13

Gg

Answer 13

• activates phospholipase C which cleaves phosphoinositides

Question 14

oligomerization

Answer 14

process of bringing the receptors close enough to phosphorylate one another

Question 15

eph receptors

Answer 15

most numerous RTK regulate cell adhesion and migration