Comparative Study of Auditory Sensitivity in Wistar Rats and Heterozygous Rats with Reduced Expression of the Dopamine Transporter DAT-1 Gene

A comparative study of characteristics of the auditory sensitivity in intact Wistar rats and heterozygous rats of transgenic DAT-HET line (dopamine transporter heterozygous) rats with reduced expression level of the Slc6a3 gene encoding the dopamine transporter 1 (DAT-1) was conducted; they represent an experimental model of dopaminergic neuron system pathology (attention deficit hyperactivity disorder). During the study, the amplitude and temporal parameters of auditory brainstem responses (recorded from the rats of both lines under presentation of paired clicks and single tones) were analyzed. The characteristics of auditory sensitivity of Wistar and DAT-HET rats were similar, but a comparative analysis of the wave amplitudes of auditory brainstem responses revealed a significantly larger amplitude of wave 1 in DAT-HET rats. Data obtained suggest that DAT-HET heterozygotes differ from rats with normally functioning dopamine transporter DAT-1 by an increased level of dopaminergic signaling associated with the activation of D1 receptors localized in the membranes of the cochlea spiral ganglion neurons.