RESUMO
We previously described stable constitutional differences in psychophysiologic reactions of dogs exposed repeatedly to psychologically stressful situations induced by Pavlovian conditioning techniques with electrocutaneous reinforcement. Some dogs (e.g., most beagles and other hounds, and some mongrels) showed high psychophysiologic adaptation (HA dogs). Other dogs (e.g., many wirehair fox terriers, border collies, German shepherds, cocker spaniels, and some mongrels) developed persistent, almost inextinguishable psychophysiologic reactions to the entire Pavlovian aversive room complex: tachycardia, polypnea, profuse salivation, vasopressin release, high energy metabolism, and high urinary catecholamines (low adaptation or LA dogs). Analysis of the development and extinction of cardiac and respiratory orienting reflexes (O.R.) in these two types of dogs indicates that the LA dogs exhibit higher frequency and more intensive, persistent, and highly fluctuating (poorly modulated) cardiac and respiratory O.R.s than those exhibited by the HA dogs, which show rapid O.R. habituation and good modulation. Insofar as one may extrapolate these data to human subjects, recording of the dynamics of the development and habituation and the degree of modulation of visceral orienting reflexes may facilitate the early detection of individuals at risk for cardio-respiratory and other psychovisceral disorders.
