Topics 5 + 6 - Effects on Rat Uterine Muscle

Question 1

What’s the first step of any rat uterine muscle experiment?

Answer 1

Wash out with tyrode solution thrice

Question 2

Which program should be used to measure the contractions of the rat uterine muscle?

Answer 2

MEASURE

Question 3

What should be the first thing you change when on the program?

Answer 3

LENGTH to 2000

Question 4

What should be calibrated on the transducer-amplifier?

Answer 4

Fine tune, 1x, and 1

Question 5

What button should you click when changing substances?

Answer 5

MARKER

Question 6

What is the effect of Calcium (Ca²⁺) on smooth muscle?

Answer 6

Ca²⁺
↓
Calmodulin
↓
Myosin Light Chain Kinase (MLCK)
↓
Actin-myosin cross bridge (contraction)

Question 7

What is the effect of Barium (Ba²⁺) on smooth muscle?

Answer 7

Ba²⁺ — 100 microliter
↓
Irreversible Noncompetitive K⁺-Blocker
⊥ (i)
Prevents repolarization (causing prolonged contraction)

Question 8

What is the effect of Papaverine on smooth muscle?

Answer 8

Papaverine — 20 microliter
⊥ (i)
Calcium Phosphodiesterase Inhibitor
↓
cAMP increase
⊥ (i)
Inhibition of MLCK (Myosin-Light-Chain-Kinase)
↓
Relaxation

Question 9

What is the effect of Magnesium (Mg²⁺) on smooth muscle?

Answer 9

Mg²⁺ — 50 microliter
↓
Competitive Ca²⁺ channel blocker
↓
Weaker contractions

Question 10

What does normal tyrode contain?

Answer 10

Physiologic solution, contains calcium for contractions

Question 11

What happens to muscle contractions after the addition of CaCl (when magnesium was first poured)?

Answer 11

Calcium outcompetes the magnesium and brings the contractions back to normal