Chronic alcohol consumption produces a painful peripheral neuropathy for which there is no reliably successful therapy, attributable to, in great part, a lack of understanding of the underlying mechanisms. We tested the hypothesis that neuropathic pain associated with chronic alcohol consumption is a result of abnormal peripheral nociceptor function. In rats maintained on a diet to simulate chronic alcohol consumption in humans, mechanical hyperalgesia was present by the fourth week and maximal at 10 weeks. Thermal hyperalgesia and mechanical allodynia were also present. Mechanical threshold of C-fibers in ethanol fed rats was lowered, and the number of action potentials during sustained stimulation increased. The hyperalgesia was acutely attenuated by intradermal injection of nonselective protein kinase C (PKC) or selective PKC⑀ inhibitors injected at the site of nociceptive testing. Western immunoblot analysis indicated a higher level of PKC⑀ in dorsal root ganglia from alcohol-fed rats, supporting a role for enhanced PKC⑀ secondmessenger signaling in nociceptors contributing to alcohol-induced hyperalgesia.Key words: protein kinase C ⑀; alcoholic peripheral neuropathy; pain; hyperalgesia; allodynia; primary afferent nociceptor Ethanol consumption is the most common cause of peripheral nervous system, as well as CNS, neurotoxicity. Ethanol is thought to exert a direct neurotoxic action on the peripheral nervous system, resulting in a neuropathy that mostly involves smalldiameter fibers (Diamond and Messing, 1994;Monforte et al., 1995;Kielhorn, 1996;Ortiz-Plata et al., 1998;Tredici et al., 1999). The peripheral neuropathy is a potentially incapacitating complication of chronic consumption of ethanol, characterized by pain and dysesthesias, primarily in the lower extremities, and is poorly relieved by available therapies (Ratcliff, 1979;Monforte et al., 1995;Ortiz-Plata et al., 1998).Whereas enhanced nociception and primary afferent nociceptor hypersensitivity have been demonstrated in animal models of other neuropathic pain states, such as those induced by diabetes (Ahlgren and Levine, 1994), chemotherapy (Tanner et al., 1998; Authier et al., 1999), or trauma (Bennett andXie, 1988;Campbell et al., 1988;Seltzer et al., 1990;Xie and Xiao, 1990;Kim and Chung, 1992;Kim et al., 1993;Sheen and Chung, 1993;Yoon et al., 1996;Pedersen and Kehlet, 1998;Zahn and Brennan, 1999), an animal model for alcohol-induced neuropathy does not exist, nor has it even been demonstrated that primary afferent nociceptor function is altered by chronic exposure to alcohol.In animal models of other painful peripheral neuropathies, enhanced nociception involves alterations in intracellular signaling. Specifically, protein kinase C (PKC) (Ahlgren and Levine, 1994) [particularly the epsilon (⑀) isoform (Gerstin et al., 1998; Khasar et al., 1999] and protein kinase A (PKA) (Ahlgren and Levine, 1994) signaling pathways have been implicated in enhancing nociceptor function. Because alcohol has been shown to activate PKC and PKA (Coe et al., 1...