title: Cochleotoxicity of amine groups.
abstract: It has previously been shown that polyamines are ototoxic. The relationship between the number of amine groups and ototoxicity was studied using spermine, spermidine and 1,3-diaminopropane, which are polyamines with differing numbers of amine groups. Fifty pigmented guinea pigs were studied by injecting 0.1 ml of different concentrations of spermine, spermidine or 1,3-diaminopropane intratympanically. The animals were sacrificed 4 days after the injection and the organ of Corti was studied by scanning electron microscopy. It was found that on an equimolar basis, spermine (with 4 amine groups) is more cochleotoxic than spermidine (with 3 amine groups), which is in turn more cochleotoxic than 1,3-diaminopropane (with 2 amine groups). The cochleotoxic potential of the amine groups may be a result of their cationic nature at physiological pH (7.4). This property might be part of the explanation of the ototoxicity of the aminoglycosides.
mesh_terms: D000818:Animals; D003051:Cochlea / Q000187:drug effects*; D003959:Diamines / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D006198:Hair Cells, Auditory / Q000187:drug effects; D009925:Organ of Corti / Q000187:drug effects; D013095:Spermidine / Q000633:toxicity*; D013096:Spermine / Q000633:toxicity*; D013329:Structure-Activity Relationship
chemical_list: D003959:Diamines; D013096:Spermine; C009475:trimethylenediamine; D013095:Spermidine