Individuals tend to focus their energies on stimuli that are particularly stimulating or engaging. Some people regard bondage to be erotically stimulating or sexually arousing. Nicotine is used widely throughout the world for its stimulating and relaxing effects. It works by stimulating melatonin receptors and blocking serotonin receptors. The effect is thought to be from stimulating inflammation and increasing oxidative stress. This has the effect of stimulating growth of plankton. Not all wavelengths are equally effective at stimulating the human eye. It also has the function of stimulating pepsinogen secretion by chief cells. Nicaragua faces a number of challenges in stimulating rapid economic growth. The article suggests a mechanism where light television entertainment crowds out more cognitively stimulating activities. In Graves' disease, for an unknown reason autoantibodies develop against the thyroid stimulating hormone receptor. Finally, Gambit was able to heal himself by stimulating his cellular activity. Sepsis is also able to prevent leucine from stimulating muscle protein synthesis. Overexpression of VEGF causes increased permeability in blood vessels in addition to stimulating angiogenesis. TENS is for blocking pain, where EMS is for stimulating muscles.