Anatomy | Mechanisms of Smooth Muscle Contraction

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PATREON

[AimeeTrainor-icyj]

this is the best video ive ever watched on this; thank you so so much!!

[hughs]

very helpful and just at the right level of detail, commenting to help the yt algorithms

[luba]

Discovered your channel recently! Amazing indeed!

[ttho]

Hi, thanks for the video! I am a little confused because I have been reading and learning about the effects of theophylline on bronchioles. From my understanding, it is a phosphodiesterase inhibitor, thus leading to an increase in cAMP concentration in smooth muscle. I have also read that cAMP inhibits myosin light chain kinase thus causing bronchodilation/ SM relaxation. I am confused because now it seems contradictory if cAMP is shown here to induce release of calcium ion from SR. Please can you help?

[randdawoud]

Thank you so much, amazing explanation!!!

[jushnita.]

How good you explained I couldn't

[TheUnseriousYoutuber]

Finally got someone who made this understandable 😂

[CassieKadrlik]

how does the actin myosin light chain get unphosphorylated what reverses it?

[TheHyperMD]

Hmmm -
- cAMP (via NE/Epi, beta 2, Gs)—> smooth muscle relaxation.

- IP3 (via NE/Epi, alpha 1, Gq)—> smooth muscle contraction.

- inhibition of cAMP (via NE/Epi, alpha 2, Gi)—> smooth muscle relaxation.

[kyforever]

I think there is a mistake with epinephrine, it works on Gq which in turn activates Phospholipase C(PLC) which then hydrolyses PIP2 giving DAG and IP3..IP3 induces the release of Ca+ etc.