Effects of neonatal thyroxine, genotype, and noise on the ear and audiogenic seizures

T. N. Seyfried et al (1979) recently reported that the DBA/2J mouse genotype, which is innately susceptible to audiogenic seizures, has high neonatal levels of thyroxine (T₄) and that neonatal injections of T₄ induced susceptibility in the C57BL/6J mouse. In the experiment, neonatal T₄ injections (20 μg) produced a temporary peripheral auditory dysfunction that appeared to be conductive in nature in the C57BL/6J mouse (n = 106). A cochlear dysfunction was also seen in the DBA/2J mouse (n = 17) and in the acoustically primed C57BL/6J mouse. Since a peripheral auditory threshold elevation in these latter groups of mice appears to be causally related to their susceptibility to audiogenic seizures, it is likely that at least a portion of the susceptibility that Seyfried et al reported was due to the effects of T₄ on the ear. (34 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).