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.
Specifically, vitamin C has been shown to stabilize collagen mRNA, thus increasing collagen protein synthesis for repair of the damaged skin (47) . This occurs concurrently with a decrease in elastin production; the elastin protein is often overproduced in response to photodamage (48) .n addition to its antioxidant functions, vitamin C regulates the synthesis of the structural protein collagen. The role of vitamin C in the hydroxylation of collagen molecules is well characterized (46) . Hydroxylation of collagen is necessary for its extracellular stability and support of the epidermis.