Auditory evoked potential in handled and non-handled iron-deficient rats

ABSTRACT

Iron deficiency alters metabolism, neurotransmission, glial integrity and the cortical myelin layer, besides increasing myelinization time. Environmental stimulation (handling) improves morphological, biochemical, electrophysiological and behavioral aspects of both well-nourished and malnourished animals. The objective of the present study was to determine the effects of an irondeficient diet and of handling on the brainstem auditory evoked potential (BAEP) of rats during development. Ninety-six male rats were divided since birth into Well-nourished (W, 35 mg iron/kg) and Anemic (A, 4 mg iron/kg) groups, and subdivided into Handling (H) and No Handling (NH). Body weight, hemoglobin (Hb), hematocrit (Ht), latencies of waves I, II, III IV, I-IV interpeak interval, and response threshold to auditory stimuli were evaluated at 18, 22, and 32 days. W animals presented higher Hb and Ht levels than A animals at 18, 22 and 32 days. The animals presented longer latencies of waves I, II, III and IV and I-IV interpeak interval of BAEP at 18 than at 22 and 32 days, and AH18 rats presented longer latencies of waves I and II than AH22 and AH32 rats, and longer wave I latency than WH18 animals. Iron deficiency increased the latencies of BAEP waves, suggesting damage to the myelin layer, especially during the early development, and the effects of handling were more evident along time in anemic animals.