Analysis of Stress Susceptibility Using the Maudsley Reactive and Non-Reactive Strains
David A. Blizard Bowman Gray School of Medicine of Wake Forest University
Coping with the uncertainty generated by social situations evokes wide differences in behavioral and physiological response patterns among primate species including man (see Kagan et al. and Levine & Wiener, this volume). There is great interest in the central nervous system (CNS) mechanisms underlying these differences: The individual variations in psychophysiological response emerge early in ontogeny, and psychologists have been willing to consider the possibility that they are genetically mediated because their early appearance is presumed less likely to be dependent on environmental influences. Genetic influences can be investigated in man but the rich variety of genetic models that exist in rodent species provide an excellent resource in this field. These models offer the usual conveniences of investigation with small, laboratory-reared animals and permit a more detailed and rigorous analysis of underlying physiological and biochemical mechanisms.
A variety of rodent genetic models exist for exploration of coping with the uncertainty generated by both social and other environmental stimuli ( Adams & Blizard, 1987; Blizard & Fulker, 1981).1 discuss research involving use of the Maudsley rat strains that were selected for differences in open-field defecation (OFD) in the United Kingdom by Peter Broadhurst in the late 1950s and early 1960s ( Broadhurst, 1960, 1962). They were developed to provide an animal model of the human personality dimension of emotionality (Eysenck, 1967) or, as more specifically enunciated by Broadhurst ( 1956) to investigate "the part