It is specifically needed in the mammalian kidney as an osmotically active compound which facilitates passive re-uptake of water into the blood. Because of this, salt elicits a pleasant taste in most humans. Sour and salt tastes can be pleasant in small quantities, but in larger quantities become more and more unpleasant to taste. For sour taste this is presumably because the sour taste can signal under-ripe fruit, rotten meat, and other spoiled foods, which can be dangerous to the body because of bacteria which grow in such media. Additionally, sour taste signals acids, which can cause serious tissue damage. Sweet taste signals the presence of carbohydrates in solution. Since carbohydrates have a very high calorie count (saccharides have many bonds, therefore much energy), they are desirable to the human body, which evolved to seek out the highest calorie intake foods. They are used as direct energy (sugars) and storage of energy (glycogen). However, there are many non-carbohydrate molecules that trigger a sweet response, leading to the development of many artificial sweeteners, including saccharin, sucralose, and aspartame. It is still unclear how these substances activate the sweet receptors and what adaptational significance this has had. The savory taste (known in Japanese as "umami") was identified by Japanese chemist Kikunae Ikeda, which signals the presence of the amino acid L-glutamate, triggers a pleasurable response and thus encourages the intake of peptides and proteins.
Sodium picosulfate (INN, also known as sodium picosulphate) is a contact stimulant laxative used as a treatment for constipation or to prepare the large bowel before colonoscopy or surgery. It is sold under the trade names Sodipic Picofast, Laxoberal, Laxoberon,  Purg-Odan, Picolax, Guttalax, Namilax, Pico-Salax, PicoPrep, and Prepopik, among others. Effects
Orally administered sodium picosulfate is generally used for thorough evacuation of the bowel, usually for patients who are preparing to undergo a colonoscopy. It takes 12–24 hours to work, since it works in the colon.Abdominal cramps and diarrhea are normal effects of picosulfate and should be expected. The use of sodium picosulfate has also been associated with certain electrolyte disturbances, such as hyponatremia and hypokalemia. Patients are often required to drink large amounts of clear fluids, to compensate for dehydration and to reestablish normal electrolyte balance. Mechanism of action
Sodium picosulfate is a prodrug. It has no significant direct physiological effect on the intestine; however, it is metabolised by gut bacteria into the active compound 4,4-dihydroxydiphenyl-(2-pyridyl)methane (DPM, BHPM). This compound is a stimulant laxative and increases peristalsis in the gut.Sodium picosulfate is typically prescribed in a combined formulation with magnesium citrate, an osmotic laxative. This combination is a highly effective laxative, often prescribed to patients for bowel cleansing prior to colonoscopies. == References ==