Question

Epinephrine (Adrenaline) is commonly used to counteract asthma attacks (when bronchi, or airways, get constricted in a spasm and block the breathing).
Explain, how that works. Which adrenergic receptors would be involved here? Answer must be at least 75 words.

Answer 1

Bronchi muscle contains beta 2 adrenergic receptors.

adrenaline acts on the beta 2 adrenergic receptors and causes bronchi muscle relaxation. So bronchi is dilated .

mechanism - adrenaline acts on the beta 2 adrenergic receptors which are GPCR receptors and produces Gd subunit. This gs subunit activates adenyl  Cyclase which converts atp to camp . CAmp activates proteinkinase A . This protein kinase A phosphorylates and inhibits myosin light chain kinase and stimulates myosin phosphatase .

Therefore it causes relaxation of bronchi smooth muscle .