NO synthesis inhibitors and NO antagonists
NO, especially when it is produced in excess, can have toxic effects, particularly in certain pathological conditions such as ischemia. Drugs able to reduce NO production, to inhibit its effects or to trap NO and peroxynitrite are being sought.
Note: nitrogen protoxide
Nitrous oxide, N2 O, also called dinitrogen oxide, is a nonflammable gas, not irritant, given by inhalation as an analgesic agent. It has been used in anesthesia for a long time to obtain analgesia of short duration, in traumatology or during painful medical acts. Inhaled, the mixture induces analgesia in a few minutes. Nitrous oxide is eliminated by pulmonary route.
Nitrous oxide can induce adverse effects: euphoria, sedation, dizziness, modification of sensory perceptions. Its use is contraindicated in pregnant woman because in animal experiments it has a teratogenic effect.
In medical personnel, working in badly ventilated operating rooms where N2 O is employed, a decrease of fertility neuropathies, anemia evoking a deficiency in vitamin B12, have been reported. Nitrous oxide interacts with the cobalt atom of vitamin B12 and thus inhibits methionine synthase.
Chronological bench marks
Arginine was isolated in 1886. Its role in the urea cycle was discovered about 1900. Its nutritional role and as precursor of creatine was highlighted in the years 1940-1950. Its endogenous biosynthesis in human beings was discovered in the 1980s.
The discovery of the role of NO as transmitter and its formation from arginine was made in the 1990s.
The use of nitrates, nitroglycerin, in therapeutics started around 1850.
The facilitator role in erection of sildenafil was discovered and determined between 1995 and 2000.
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