Reduced conduction function in central nervous system by 2,5-hexanedione

Abstract

In order to examine the involvement of the central nervous system (CNS) following administration of 2,5-hexanedione (2,5-HD) in rats, the present experiment was conducted using the auditory brainstem response (ABR) and somatosensory-evoked potentials (SEPs). Nine male Wistar rats were given 2,5-HD subcutaneously at 350 mg/kg/day, five days a week for three weeks. For the control group, nine male rats were employed. One week after the last administration, ABRs were measured from the scalp with subcutaneous needle electrodes under pentobarbital anesthesia. Click sounds of 61 and 86 dB sound pressure level were used in ABR measurement (61dB-ABR and 86dB-ABR, respectively). The SEP evoked by stimulation at the forepaw and the medulla oblongata (SEP and SEP-M) were recorded from the surface of the cerebral cortex using screw electrodes under immobilization. The significant findings observed in 2,5-HD-treated rats included: 1) delayed latencies of the Ist, IIIrd, IVth and Vth components of the 61dB-ABR and the Ist, IInd, IIIrd and Vth components of the 86dB-ABR; 2) increased interpeak latencies (IPLs) between III-V and I-V of the 61dB-ABR; 3) delayed latencies of the P1 and N1 components of the SEP and the N1 component of the SEP-M. The delays of IPL-III-V of the 61dB-ABR and the N1 component of the SEP-M were considered to reflect conduction disorders of the auditory and somatosensory afferent pathway in the CNS, respectively. Thus, the ABR may be a sensitive method to detect disorders in the CNS produced by neurotoxic substances.