Neuroendocrine and behavioral correlates of constitutional differences

Consistent and stable individual differences were observed in the renal responses of water-loaded dogs during the development of Pavlovian conditional motor defense reflexes by electrocutaneous reinforcement. Some dogs developed persistent and intense conditional antidiuretic responses (with a high urine osmolality) to the entire Pavlovian conditioning room complex, whereas other dogs failed to exhibit conditional antidiuresis. In contradistinction to the conditional motor defense reflexes, the conditional antidiuretic responses showed poor differentiation, thus demonstrating the phenomenon of schizokinesis discovered by Gantt. In addition to conditional water retention, the antidiuretic dogs also exhibited persistent hyperpnea, copious salivation and tachycardia. The physiologic responses of the antidiuretic dogs to the Pavlovian conditioning room resemble those described by Walter B. Cannon for a “fight or flight” response,i.e., physiologic reactions of animals engaged in intense muscular effort. The antidiuresis serves the function of conserving body water so that it may be available for evaporative cooling in order to maintain thermal homeostasis. Since our experimental dogs cannot engage in a consummatory “fight or flight” response, their physiologic reaction to a stressful psychologic environment can be considered maladaptive. Pharmacologic analysis suggested that the antidiuretic responses may involve cholinergic transmitters.