BEHAVIORAL, HISTOLOGICAL, AND NEUROCHEMICAL EFFECTS OF NICKEL-(II) ONTHE RAT OLFACTORY SYSTEM

Experimentally, inorganic, sulfated nickel compounds (Ni2+) have been shown to produce histological lesions in the nasal mucosa of rats, mor e specifically, atrophy of the olfactory epithelium. The present proje ct was designed to assess the effects of inhalation of nickel sulfate hexahydrate on behavioral, histological, and neurochemical aspects of the olfactory system. Male Long-Evans rats were exposed to either back ground air (control) or 635 mu g Ni/m(3) for 16 consecutive days, 6 hr /day. Exposure resulted in selective lesions to the olfactory epitheli um. The number of bipolar sensory receptor cells was slightly reduced and there was a significant decrease in the thickness of the olfactory epithelium. This was due primarily to a significant loss of the suste ntacular cell population, with a thinning of the apical cytoplasm, con comitant with a reduction in the number of microvilli at the surface o f these cells. Significant decreases in carnosine level, consistent wi th the nickel sulfate exposure, were observed. However, there were no changes in olfactory function as measured by either absolute threshold or two-odor discrimination tasks. (C) 1995 Academic Press, Inc.