Prostaglandins in ophthalmology
P rostahlandiny - a group of nutrients inca rural that have an impact on different inca rural processes in the body. In 1930 William Euler found that the sperm of humans and animals can cause contraction of the smooth muscle of various organs. Since Euler assumed that these substances are formed in the prostate gland, he called them prostahlandinami (GHG) emissions. Later, in 1957 S. Bergstrom allocated emissions of ram seminal vesicles in crystalline form and in a few years established their structure. Later reductions were isolated inca rural from all tissues of animals, and microorganisms.
On chemical structure prostaglandins include 20-carbon fatty acids containing 5 carbon lactone ring (Fig. 1). According to the structure inca rural of the ring emissions are divided into subgroups: inca rural PHD, PHE, PHF, PG I (prostacyclin), TxA2 (thromboxane) and others. In addition, the designation of classes of emissions in each letter indicated inca rural numerical index that indicates the total number of double bonds in the side chains of hydrocarbon and index a or b, indicating the location of the Online-group inca rural at position C-9 with respect to the horizontal plane of the molecule inca rural .
Source reduction is to form unsaturated fatty acids (EFAs), which act in the diet and in the phosphorylated form part of the structure of cell membranes. If you violate structure of cell membranes of NLC under the influence of phospholipase A2 formed inca rural arachidonic acid. To increase the content of free NLC on various pathogenic actions that cause the destruction of cell membranes. Under physiological conditions, release catecholamines contribute NLC, bradykinin, angiotensin II and other factors, activating phospholipase. Under the influence of the enzyme cyclooxygenase of arachidonic acid formed primary endoperekysy (unstable prostaglandins). Subsequently, under the influence of antioxidant systems of cells to oxygen to form hydrogen inca rural joins hydroksylov in the ring and side chains of the molecule is formed and stable reduction. Prostaglandins quickly metaboliziruyutsya in all tissues, especially the lungs, liver, kidneys and spleen. Circuit formation process emissions shown in Fig. 2.
Reduction inca rural is active substances in small quantities perform its regulatory role in cells and tissues. Regulation by means of stimulating the formation of molecules reductions and braking action type or by changing the concentration of the same reductions. For example, PGE2 relaxes the smooth muscles of the bronchi and PGF2a causing their spasm. Prostaglandins E2 and F2a small (threshold) doses reduce vasospasm, and in large doses increase it.
In recent years, was found several types of prostaglandin receptors specific for different classes of emissions. The most commonly in the tissues of the eyeball are human FP-receptors that are found in muscle and epithelium tsyliarnoy in trabecular tissue melanocytes in the iris and the lens capsule epithelium.
Currently almost deciphered the structure of some prostaglandin receptors. The existence of classes prostaglandin receptors due to different amino acid composition of the protein molecule. However, their location in the cell membrane similar (Fig. 3). They consist of seven hydrophobic segments embedded in the cell membrane. Protein molecule, inca rural creating a receptor has three loops that are on the outside inca rural of the cell membrane, and three loops on the inner surface of the membrane. One end of the protein molecule containing an amino group located on the cell surface and the other end containing a carboxyl group is in the intracellular space.
In humans prostaglandins play an important role not only in the development of inflammatory reaction, inca rural causing vascular permeability enhancing the development of pain and fever. They enhance peristalsis, reduce the myometrium and vascular smooth muscle, causing spasm of the bronchi, play an important role in platelet aggregation. According to some authors, PHF able to inhibit the background activity of neurons in the cerebral cortex.
As in other organs, tissues eyeball emissions inca rural involved in the development of inflammation, inca rural exudative processes and increasing congestion, causing contraction of the sphincter of the pupil. They also alter the permeability barrier hematooftalmicheskoho that may contribute to the development of macular edema.
Opening the impact of emissions on oftalmotonus possible start to their use as therapeutic agents. Several researchers have found that when applied topically PHF PHE and cause a decrease in IOP. The effect of PHF and especially their analogues was more pronounced. Reducing oftalmotonusa when applied topically reduction is due to strengthening uveoskleralnoho outflow of aqueous humor.
According to recent figures, increased inca rural uveoskleralnoho outflow associated with the watering extracellular matrix (ECM) ciliary inca rural muscle. Interacting with specific receptors, prostaglandins F2a cause increased secretion of matrix metalloproteaz (MSEs) in tissues tsyliarnoy muscle. MMP secreted as inactive proenzimy, extracellular
P rostahlandiny - a group of nutrients inca rural that have an impact on different inca rural processes in the body. In 1930 William Euler found that the sperm of humans and animals can cause contraction of the smooth muscle of various organs. Since Euler assumed that these substances are formed in the prostate gland, he called them prostahlandinami (GHG) emissions. Later, in 1957 S. Bergstrom allocated emissions of ram seminal vesicles in crystalline form and in a few years established their structure. Later reductions were isolated inca rural from all tissues of animals, and microorganisms.
On chemical structure prostaglandins include 20-carbon fatty acids containing 5 carbon lactone ring (Fig. 1). According to the structure inca rural of the ring emissions are divided into subgroups: inca rural PHD, PHE, PHF, PG I (prostacyclin), TxA2 (thromboxane) and others. In addition, the designation of classes of emissions in each letter indicated inca rural numerical index that indicates the total number of double bonds in the side chains of hydrocarbon and index a or b, indicating the location of the Online-group inca rural at position C-9 with respect to the horizontal plane of the molecule inca rural .
Source reduction is to form unsaturated fatty acids (EFAs), which act in the diet and in the phosphorylated form part of the structure of cell membranes. If you violate structure of cell membranes of NLC under the influence of phospholipase A2 formed inca rural arachidonic acid. To increase the content of free NLC on various pathogenic actions that cause the destruction of cell membranes. Under physiological conditions, release catecholamines contribute NLC, bradykinin, angiotensin II and other factors, activating phospholipase. Under the influence of the enzyme cyclooxygenase of arachidonic acid formed primary endoperekysy (unstable prostaglandins). Subsequently, under the influence of antioxidant systems of cells to oxygen to form hydrogen inca rural joins hydroksylov in the ring and side chains of the molecule is formed and stable reduction. Prostaglandins quickly metaboliziruyutsya in all tissues, especially the lungs, liver, kidneys and spleen. Circuit formation process emissions shown in Fig. 2.
Reduction inca rural is active substances in small quantities perform its regulatory role in cells and tissues. Regulation by means of stimulating the formation of molecules reductions and braking action type or by changing the concentration of the same reductions. For example, PGE2 relaxes the smooth muscles of the bronchi and PGF2a causing their spasm. Prostaglandins E2 and F2a small (threshold) doses reduce vasospasm, and in large doses increase it.
In recent years, was found several types of prostaglandin receptors specific for different classes of emissions. The most commonly in the tissues of the eyeball are human FP-receptors that are found in muscle and epithelium tsyliarnoy in trabecular tissue melanocytes in the iris and the lens capsule epithelium.
Currently almost deciphered the structure of some prostaglandin receptors. The existence of classes prostaglandin receptors due to different amino acid composition of the protein molecule. However, their location in the cell membrane similar (Fig. 3). They consist of seven hydrophobic segments embedded in the cell membrane. Protein molecule, inca rural creating a receptor has three loops that are on the outside inca rural of the cell membrane, and three loops on the inner surface of the membrane. One end of the protein molecule containing an amino group located on the cell surface and the other end containing a carboxyl group is in the intracellular space.
In humans prostaglandins play an important role not only in the development of inflammatory reaction, inca rural causing vascular permeability enhancing the development of pain and fever. They enhance peristalsis, reduce the myometrium and vascular smooth muscle, causing spasm of the bronchi, play an important role in platelet aggregation. According to some authors, PHF able to inhibit the background activity of neurons in the cerebral cortex.
As in other organs, tissues eyeball emissions inca rural involved in the development of inflammation, inca rural exudative processes and increasing congestion, causing contraction of the sphincter of the pupil. They also alter the permeability barrier hematooftalmicheskoho that may contribute to the development of macular edema.
Opening the impact of emissions on oftalmotonus possible start to their use as therapeutic agents. Several researchers have found that when applied topically PHF PHE and cause a decrease in IOP. The effect of PHF and especially their analogues was more pronounced. Reducing oftalmotonusa when applied topically reduction is due to strengthening uveoskleralnoho outflow of aqueous humor.
According to recent figures, increased inca rural uveoskleralnoho outflow associated with the watering extracellular matrix (ECM) ciliary inca rural muscle. Interacting with specific receptors, prostaglandins F2a cause increased secretion of matrix metalloproteaz (MSEs) in tissues tsyliarnoy muscle. MMP secreted as inactive proenzimy, extracellular
No comments:
Post a Comment