TY - JOUR
T1 - Delayed startle sensitization distinguishes rats exposed to one or three stress sessions
T2 - Further evidence toward an animal model of PTSD
AU - Servatius, Richard J.
AU - Ottenweller, John E.
AU - Natelson, Benjamin H.
N1 - Funding Information:
This research was supported by DVA Medical Research funds. The authors wish to thank Michael T. Bergen and Scott Soldan for their engineering support related to the startle apparatus. We greatly appreciate the technical assistance of Jennifer L. Gross.
PY - 1995/10/15
Y1 - 1995/10/15
N2 - Posttraumatic stress disorder (PTSD) may occur in humans exposed chronically to stressors or after a single exposure to a traumatic event. A distinguishing feature of patients with PTSD is an exaggerated startle response, evident long after the traumatic event. We have observed similar abnormalities in our animal model of a chronic stress state. Rats exposed to 3 days (3DS) of our stress regimen (2-hr sessions of 40, 2 mA tailshocks) have exhibited a consistent pattern of persistent physiological and behavioral abnormalities including an exaggerated startle response several days after stressor cessation. In contrast, rats exposed to a single stress session (1DS) have exhibited many, but not all, of the persistent abnormalities displayed by 3DS rats. The present experiment compared the startle responding of 3DS and 1DS rats 4, 7, and 10 days after stressor cessation. Consistent with previous work, stressed rats exhibited elevated basal plasma corticosterone (CORT) levels the first day poststressor. These CORT levels were sensitive to the number of stressor exposures with higher CORT levels in 3DS rats than in 1DS rats. As for startle responding, the 1DS rats exhibited an exaggerated startle response 7 days poststressor, whereas startle sensitization was apparent 10 days poststressor in 3DS rats. Thus, the appearance of an exaggerated startle response after stressor cessation appears to be related to the number of stress session exposures. These animal models, the 3DS and 1DS rats, may be useful to gain insight into the neurobehavioral changes associated with PTSD.
AB - Posttraumatic stress disorder (PTSD) may occur in humans exposed chronically to stressors or after a single exposure to a traumatic event. A distinguishing feature of patients with PTSD is an exaggerated startle response, evident long after the traumatic event. We have observed similar abnormalities in our animal model of a chronic stress state. Rats exposed to 3 days (3DS) of our stress regimen (2-hr sessions of 40, 2 mA tailshocks) have exhibited a consistent pattern of persistent physiological and behavioral abnormalities including an exaggerated startle response several days after stressor cessation. In contrast, rats exposed to a single stress session (1DS) have exhibited many, but not all, of the persistent abnormalities displayed by 3DS rats. The present experiment compared the startle responding of 3DS and 1DS rats 4, 7, and 10 days after stressor cessation. Consistent with previous work, stressed rats exhibited elevated basal plasma corticosterone (CORT) levels the first day poststressor. These CORT levels were sensitive to the number of stressor exposures with higher CORT levels in 3DS rats than in 1DS rats. As for startle responding, the 1DS rats exhibited an exaggerated startle response 7 days poststressor, whereas startle sensitization was apparent 10 days poststressor in 3DS rats. Thus, the appearance of an exaggerated startle response after stressor cessation appears to be related to the number of stress session exposures. These animal models, the 3DS and 1DS rats, may be useful to gain insight into the neurobehavioral changes associated with PTSD.
KW - Posttraumatic stress disorder
KW - startle sensitization
UR - http://www.scopus.com/inward/record.url?scp=0028861066&partnerID=8YFLogxK
U2 - 10.1016/0006-3223(94)00369-E
DO - 10.1016/0006-3223(94)00369-E
M3 - Article
C2 - 8562666
AN - SCOPUS:0028861066
SN - 0006-3223
VL - 38
SP - 539
EP - 546
JO - Biological Psychiatry
JF - Biological Psychiatry
IS - 8
ER -