Inhibition of Adenylate Cyclase: The muscarinic receptor, through interaction with an inhibitory GTP-binding protein, acts to inhibit adenylyl cyclase. Reduced cAMP production leads to reduced activation of cAMP-dependent protein kinase, reduced heart rate, and contraction strength.
Scleroderma, a rare autoimmune disease characterized by abnormal connective tissue growth, can wreak havoc on everything from the skin and heart to lungs, teeth, speech, and movement. The overproduction of collagen causes the skin and organs to harden, leading them to atrophy and possibly fail.
As well as being naturally lost through age, there are also some other environmental stresses that cause a loss of collagen, leaving the skin loose, dry, wrinkled, lined and saggy: Our skin is very sensitive to the sun, so prolonged sun exposure damages the skin cells and in turn the collagen production.