DYNAMICS OF PLASMA-CATECHOLAMINE AND CORTICOSTERONE CONCENTRATIONS DURING REINFORCED AND EXTINGUISHED OPERANT-BEHAVIOR IN RATS

Plasma noradrenaline (NA), adrenaline (A) and corticosterone (CS) concentrations were determined simulataneously in permanently heart-cannulated rats before and during the performance of reinforced and nonreinforced (extinguished) operant behavior. Shortly before the experimental food-reinforced (VI 15-sec schedule) lever-pressing task, anticipatory elevations of plasma NA and CS contents were observed. During reinforced lever responding plasma NA increased, A did not change and CS declined. Extinction was associated with a transient increase in A, decreasing NA and elevated CS concentrations. In addition, a relationship was found between individual lever-pressing rate, neurosympathetic and adrenomedullary reactivity and the degree of schedule-induced polydipsia. The results indicate that presence and absence of expected behavioral consequences (controllability and loss of control, respectively) are attended by selective, but highly dissociated patterns of neurosympathetic, adrenomedullary and adrenocortical output. Collectively, the findings reinforce the concept that distinctive emotional and/or motivational states are associated with different patterns of neuroendocrine responses. The reactivity of the sympathoadrenomedullary component is heavily dependent upon a rat's individual behavioral strategy. © 1990.