A conspecific attenuates prolactin responses to open-field exposure in rats.
Acute exposure to a novel environment, such as an open field, generally results in a prolactin surge, while several days of exposure to the open field is often characterized by a decline in prolactin. As exposure to the open field is a psychological stressor, altering the animal's interpretation of the event should alter prolactin levels. In the present study, juvenile male and female rats were habituated to the open field for 1 or 5 days prior to testing in the chamber alone or with a same-sex conspecific. Levels of prolactin were measured across all rats, and play (pins) was recorded for animals tested with a conspecific. Five days of habituation to the chamber resulted in lower levels of prolactin and more play than 1 day of habituation. Across both conditions of habituation, testing with a conspecific caused lower levels of prolactin than testing alone. In addition, play and prolactin were negatively correlated. The presence of a conspecific in a stressful situation may have reduced stress by altering the animal's negative interpretation of the open field. Further, as the intensity of the social interaction increased (more play), prolactin levels decreased.
Georgia Southern University, Statesboro, Georgia 30460, USA.
J H
JH
Wilson
D000818:Animals; D001143:Arousal / Q000502:physiology*; D005106:Exploratory Behavior / Q000502:physiology*; D005260:Female; D006185:Habituation, Psychophysiologic / Q000502:physiology; D008297:Male; D011388:Prolactin / Q000097:blood*; D051381:Rats; D020318:Rats, Long-Evans; D012931:Social Environment
D011388:Prolactin