Effects of aromatic solvents on acoustic reflexes

Chronic exposure to toluene (Tol) can impair the central nervous system (Yamanouchi et al. 1995; Greenberg 1997). Tol shares many effects with nervous system depressant compounds such as anesthetics (Evans & Balster 1991). In the past, the neuroactivity of anesthetics and related compounds was thought to be attributed to their ability to perturb the plasma membrane (Engelke et al. 1992). Today, clear evidence is emerging from the literature regarding actions of solvents on ion channels expressed in neurons. For instance, NMDA (Cruz et al. 1998), GABA (Krasowski & Harrison 2000) and Ach (Bale et al. 2002) receptors are important to nervous system and sensitive to Tol. Besides, Tol alters the function of several voltage-dependent ion channels including voltage-dependent Ca channels (VDCCs) (Tillar et al. 2002; Shafer et al. 2005). Chronic exposure to Tol can impair the inner ear as well (Odkvist et al. 1982; Rybak 1986). The notion of ototoxicity stemming from organic compounds is important for people exposed at workplace (Morata & Campo 2001). Certain aromatic solvents are ototoxic and can even worsen the effects of noise (Lataye & Campo 1997; Lataye et al. 2000; Brandt-Lassen et al. 2000; Cappaert et al. 2001; Sliwinska-Kowalska et al. 2003; Chang et al. 2006).