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.
In someone suffering with scleroderma, collagen (a protein manufactured by the connective tissues of the body) is produced in excess. This over-production of collagen can be likened to the process of scarring, which is the way the body heals a wound. For persons with scleroderma, the scarring gets out of hand.
One fourth to one third of all the protein in the body is collagen protein. Aging causes collagen protein to break down, leading to thinner, less elastic skin, weaker connective tissues, wrinkles, and other visible and non-visible signs of age.