Environmental Health Perspectives 105, Supplement 2, March 1997 working group report


Testing the Neural Sensitization and Kindling Hypothesis for Illness from Low Levels of Environmental Chemicals

Iris R. Bell,1 John Rossi III,2 Mary E. Gilbert,3 Gerd Kobal,4 Lisa A. Morrow,5 David B. Newlin,6 Barbara A. Sorg,7 and Ronald W. Wood8

1 Departments of Psychiatry, Psychology, and Family and Community Medicine, University of Arizona, and the Tucson Veterans Affairs Medical Center, Tucson, Arizona
2 Naval Medical Research Institute Detachment (Toxicology), Tri-Service Toxicology Consortium, Wright-Patterson Air Force Base, Ohio
3 1 U.S. Environmental Protection Agency, Research Triangle Park, North Carolina
4 1 Department of Pharmacology and Toxicology, University of Erlangen-Nurnberg, Erlangen, Germany
5 Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
6 National Institute of Drug Abuse, Baltimore, Maryland
7 Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State University, Pullman, Washington
8 Department of Environmental Medicine, New York University, New York, New York

Abstract
Sensitization in the neuroscience and pharmacology literatures is defined as progressive increase in the size of a response over repeated presentations of a stimulus. Types of sensitization include stimulant drug-induced time-dependent sensitization (TDS), an animal model related to substance abuse, and limbic kindling, an animal model for temporal lobe epilepsy. Neural sensitization (primarily nonconvulsive or subconvulsive) to the adverse properties of substances has been hypothesized to underlie the initiation and subsequent elicitation of heightened sensitivity to low levels of environmental chemicals. A corollary of the sensitization model is that individuals with illness from low-level chemicals are among the more sensitizable members of the population. The Working Group on Sensitization and Kindling identified two primary goals for a research approach to this problem: to perform controlled experiments to determine whether or not sensitization to low-level chemical exposures occurs in multiple chemical sensitivity (MCS) patients; and to use animal preparations for kindling and TDS as nonhomologous models for the initiation and elicitation of MCS. -- Environ Health Perspect 105(Suppl 2):539-547 (1997)

Key words: sensitization, kindling, mesolimbic, human, animal, time factors, low-level exposures, psychophysiology

This paper is based on a work group discussion at the Conference on Experimental Approaches to Chemical Sensitivity held 20-22 September 1995 in Princeton, New Jersey. Manuscript received at EHP 6 March 1996; manuscript accepted 6 December 1996.
Address correspondence to Dr. I.R. Bell, Department of Psychiatry, Tucson Veterans Affairs Medical Center, 3601 S. 6th Avenue, Mail Stop 116A, Tucson, AZ 85723. Telephone: (520) 792-1450, ext. 6392. Fax: (520) 629-4632. E-mail: ibell@ccit.arizona.edu
Abbreviations used: CNS, central nervous system; DSM, Diagnostic and Statistical Manual; EEG, electroencephalography; EMG, electromyography; ERP, event-related potential; MCS, multiple chemical sensitivity; MMPI, Minnesota Multiphasic Personality Inventory; POMS, Profile of Mood States scale; PTSD, posttraumatic stress disorder; SCID, Structured Clinical Interview for DSM; SCL-90-R, Symptom Checklist 90 (revised); TDS, time-dependent sensitization; TLE, temporal lobe epilepsy.

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Last Update: March 26, 1997