Metachromasia as the key to aminoglycoside ototoxicity. Preliminary report.
In in-vitro experiments, it was shown that aminoglycosides, in contrast to other antibiotics, inhibited the metachromatic reaction using o-toluidine blue as a basic dye and heparin-Na as a polysulfate-polysaccharide substrate. The inhibitory concentrations were inversely proportional to the free amino groups of aminoglycosides tested. Taking into consideration (a) that the aminoglycosides antagonize the presence of Ca++ and (b) that mechanisms of ototoxicity involve ionic alterations in endolymph, we suggest that: aminoglycoside ototoxicity could be the result of the reaction between aminoglycosides and anionic polyelectrolytes, of the group of polysulfated polysaccharides, in a metachromatic process.
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000633:toxicity; D002118:Calcium / Q000378:metabolism; D055598:Chemical Phenomena; D002621:Chemistry; D007758:Ear, Inner / Q000378:metabolism; D034381:Hearing Loss / Q000139:chemically induced*; D006493:Heparin; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D014048:Tolonium Chloride
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D014048:Tolonium Chloride; D006493:Heparin; D012964:Sodium; D011188:Potassium; D002118:Calcium