[The influence of local anesthetics on corneal epithelium. A scanning electron microscopic study (author's transl)]. 1978

H Brewitt, and H Honegger

The effect of different local anesthetics (Cocain 4%, Lidocaine 2%, Proparacain) on the corneal epithelium in rabbits was examined under scanning electron microscope. The experiment was divided into three groups. Group 1 received one application of two drops of the given local anesthetic for a reaction time of 5 minutes. Group 2 received two drops of the given anesthetic after 0, 5 and 10 minutes. The cornea was excised after 15 minutes. Group 3 were measured after a single application of Proparacain using a Schiƶtz or hand applanation tonometer according to Draeger. After a single dose of a local anesthetic principally the same changes in the surface of the cornea were observed with all the preparations used: a distinct decrease in the number of microvilli and microplicae, disruption of the intercellular spaces and the prominence of the cell nuclei which under normal conditions are not visible. After several applications the greater toxicity of Cocain compared with the other preparations was clearly seen through the disruption of the plasma membrane and the cytoplasm. The damage effected several layers of cells. Tonometry when correctly performed causes no additional damage to the cell surface.- The effect of local anesthetics on the cell membrane can only take place after the disruption of the tear film. The results emphasize that local anesthetics should only be applied when absolutely essential.

UI MeSH Term Description Entries
D008012 Lidocaine A local anesthetic and cardiac depressant used as an antiarrhythmia agent. Its actions are more intense and its effects more prolonged than those of PROCAINE but its duration of action is shorter than that of BUPIVACAINE or PRILOCAINE. Lignocaine,2-(Diethylamino)-N-(2,6-Dimethylphenyl)Acetamide,2-2EtN-2MePhAcN,Dalcaine,Lidocaine Carbonate,Lidocaine Carbonate (2:1),Lidocaine Hydrocarbonate,Lidocaine Hydrochloride,Lidocaine Monoacetate,Lidocaine Monohydrochloride,Lidocaine Monohydrochloride, Monohydrate,Lidocaine Sulfate (1:1),Octocaine,Xylesthesin,Xylocaine,Xylocitin,Xyloneural
D008855 Microscopy, Electron, Scanning Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY. Scanning Electron Microscopy,Electron Scanning Microscopy,Electron Microscopies, Scanning,Electron Microscopy, Scanning,Electron Scanning Microscopies,Microscopies, Electron Scanning,Microscopies, Scanning Electron,Microscopy, Electron Scanning,Microscopy, Scanning Electron,Scanning Electron Microscopies,Scanning Microscopies, Electron,Scanning Microscopy, Electron
D011430 Propoxycaine A local anesthetic of the ester type that has a rapid onset of action and a longer duration of action than procaine hydrochloride. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1017) Propoxyprocaine,Propoxycaine Hydrochloride,Hydrochloride, Propoxycaine
D011817 Rabbits A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes. Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D003042 Cocaine An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake. Cocaine HCl,Cocaine Hydrochloride,HCl, Cocaine,Hydrochloride, Cocaine
D003315 Cornea The transparent anterior portion of the fibrous coat of the eye consisting of five layers: stratified squamous CORNEAL EPITHELIUM; BOWMAN MEMBRANE; CORNEAL STROMA; DESCEMET MEMBRANE; and mesenchymal CORNEAL ENDOTHELIUM. It serves as the first refracting medium of the eye. It is structurally continuous with the SCLERA, avascular, receiving its nourishment by permeation through spaces between the lamellae, and is innervated by the ophthalmic division of the TRIGEMINAL NERVE via the ciliary nerves and those of the surrounding conjunctiva which together form plexuses. (Cline et al., Dictionary of Visual Science, 4th ed) Corneas
D003316 Corneal Diseases Diseases of the cornea. Corneal Disease,Disease, Corneal,Diseases, Corneal
D004848 Epithelium The layers of EPITHELIAL CELLS which cover the inner and outer surfaces of the cutaneous, mucus, and serous tissues and glands of the body. Mesothelium,Epithelial Tissue,Mesothelial Tissue,Epithelial Tissues,Mesothelial Tissues,Tissue, Epithelial,Tissue, Mesothelial,Tissues, Epithelial,Tissues, Mesothelial
D000779 Anesthetics, Local Drugs that block nerve conduction when applied locally to nerve tissue in appropriate concentrations. They act on any part of the nervous system and on every type of nerve fiber. In contact with a nerve trunk, these anesthetics can cause both sensory and motor paralysis in the innervated area. Their action is completely reversible. (From Gilman AG, et. al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed) Nearly all local anesthetics act by reducing the tendency of voltage-dependent sodium channels to activate. Anesthetics, Conduction-Blocking,Conduction-Blocking Anesthetics,Local Anesthetic,Anesthetics, Topical,Anesthetic, Local,Anesthetics, Conduction Blocking,Conduction Blocking Anesthetics,Local Anesthetics,Topical Anesthetics
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia

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