The Journal of Neuroscience, November 15, 2000, 20(22):8614-8619
Key Role for the Epsilon Isoform of Protein Kinase C in Painful
Alcoholic Neuropathy in the Rat
Olayinka A.
Dina1,
Justine
Barletta1,
Xiaojie
Chen1,
Annick
Mutero1,
Annick
Martin2,
Robert O.
Messing2, and
Jon D.
Levine1
1 Departments of Medicine and Oral and Maxillofacial
Surgery, Division of Neuroscience and Biomedical Sciences Program,
National Institutes of Health Pain Center (UCSF), University of
California at San Francisco, San Francisco, California 94143-0440, and
2 Department of Neurology, University of California at San
Francisco and Ernest Gallo Clinic and Research Center, Emeryville,
California 94608
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
second-messenger signaling in nociceptors contributing to
alcohol-induced hyperalgesia.
Key words:
protein kinase C
; alcoholic peripheral neuropathy; pain; hyperalgesia; allodynia; primary afferent nociceptor
Copyright © 2000 Society for Neuroscience 0270-6474/00/20228614-06$05.00/0