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.
How effectively iodine tablets prevent the absorption of radioactive iodine depends on: 1  How much time elapses between exposure to radioactive iodine and the consumption of iodine tablets. 2  How fast non-radioactive iodine is absorbed into the blood.  How much radioactive iodine a person is exposed to.