Like the M 1 and M 3 muscarinic receptor, M 5 receptors are coupled with G proteins of class Gq that upregulate phospholipase C and, therefore, inositol trisphosphate and intracellular calcium as a signaling pathway.
Radioactive iodine is a very effective type of treatment for cancer of the thyroid gland. Thyroid cells absorb iodine. The radioactive iodine from the drink or capsule is absorbed into your body and picked up by the thyroid cancer cells wherever they are. So it can kill the cancer cells even if they have spread.
Iodine is an important trace element in every cell of the body, including the developing brain, and it is actually concentrated in every gland of the body. It has long been known that iodine has powerful antiviral, antibacterial and immune-supporting properties. But, recently, it has been theorized that iodine can have a protective effect against cancer of both the breast and prostate.