It does this by binding to oxyhaemoglobin to release cyanide, methaemoglobin and nitric oxide. NO activates guanylate cyclase in vascular smooth muscle and increases intracellular production of cGMP. cGMP activates protein kinase G which activates phosphatases which inactivate myosin light chains. Myosin light chains are involved in smooth muscle contraction. The result is vascular smooth muscle relaxation, which allow vessels to dilate. This mechanism is similar to that of phosphodiesterase 5 (PDE5) inhibitors such as sildenafil (Viagra) and tadalafil (Cialis), which elevate cGMP concentration by inhibiting its degradation by PDE5.A role for NO in various common psychiatric disorders including schizophrenia, bipolar disorder and major depressive disorder has been proposed and supported by several clinical findings. These findings may also implicate the potential of drugs that alter NO signalling such as SNP in their treatment. Such a role is also supported by the findings of the recent SNP clinical trial. Structure and properties
Nitroprusside is an inorganic compound with the formula Na2[Fe(CN)5NO], usually encountered as the dihydrate, Na2[Fe(CN)5NO]·2H2O. This red-colored sodium salt dissolves in water or ethanol to give solutions containing the free complex dianion [Fe(CN)5NO]2−. Nitroprusside is a complex anion that features an octahedral iron(II) centre surrounded by five tightly bound cyanide ligands and one linear nitric oxide ligand (Fe-N-O angle = 176.2 °). The anion possesses idealized C4vsymmetry. Due to the linear Fe-N-O angle, the relatively short N-O distance of 113 pm and the relatively high stretching frequency of 1947 cm−1, the complex is formulated as containing an NO+ ligand.
Primary
Primary occlusal trauma occurs when greater than normal occlusal forces are placed on teeth, as in the case of parafunctional habits, such as bruxism or various chewing or biting habits, including but not limited to those involving fingernails and pencils or pens. The associated excessive forces can be grouped into three categories. Excesses of:
Duration
Frequency and
MagnitudePrimary occlusal trauma will occur when there is a normal periodontal attachment apparatus and, thus, no periodontal disease. Secondary
Secondary occlusal trauma occurs when normal or excessive occlusal forces are placed on teeth with compromised periodontal attachment, thus contributing harm to an already damaged system. As stated, secondary occlusal trauma occurs when there is a compromised periodontal attachment and, thus, a pre-existing periodontal condition. Cause and treatment
Teeth are constantly subject to both horizontal and vertical occlusal forces. With the center of rotation of the tooth acting as a fulcrum, the surface of bone adjacent to the pressured side of the tooth will undergo resorption and disappear, while the surface of bone adjacent to the tensioned side of the tooth will undergo apposition and increase in volume.In both primary and secondary occlusal trauma, tooth mobility might develop over time, with it occurring earlier and being more prevalent in secondary occlusal trauma. To treat mobility due to primary occlusal trauma, the cause of the trauma must be eliminated. Likewise for teeth subject to secondary occlusal trauma, though these teeth may also require splinting together to the adjacent teeth so as to eliminate their mobility.