TY - JOUR
T1 - Increased septal 5-HIAA efflux in rats that do not develop learned helplessness after inescapable stress
AU - Ronan, Patrick J.
AU - Steciuk, Mark
AU - Kramer, Gerald L.
AU - Kram, Martin
AU - Petty, Frederick
PY - 2000/7/1
Y1 - 2000/7/1
N2 - Learned helplessness is a behavioral deficit that can be induced by exposure to inescapable stress. Previous studies have implicated the lateral septum in mediating this phenomenon, and in this brain region, serotonin plays an important role in the development, maintenance, prevention, and reversal of learned helplessness behavior. Using the technique of in vivo microdialysis, we measured the efflux of serotonin (5-HT), dopamine (DA), and their respective metabolites, 5-hydroxyindoleacetic acid (5-HIAA) and 3,4- dihydroxyphenylacetic acid (DOPAC), from the lateral septum of rats that either developed or did not develop learned helplessness. During the microdialysis session all rats were subjected to restraint stress. Control groups included naive, home cage rats as well as tested control rats that were subjected to the identical handling, restraint, and shuttlebox testing as the rats that received inescapable shock. Overall, levels of 5-HIAA were significantly higher in non-helpless rats. There were no significant effects of restraint or differences in levels of 5-HT, DA, or DOPAC. We propose that this increase in 5-HIAA is indicative of an overall increase in serotonin metabolism in the lateral septum of rats that do not become helpless after inescapable stress. This increased serotonin metabolism in the lateral septum may protect the animal from adverse behavioral consequences of inescapable stress.
AB - Learned helplessness is a behavioral deficit that can be induced by exposure to inescapable stress. Previous studies have implicated the lateral septum in mediating this phenomenon, and in this brain region, serotonin plays an important role in the development, maintenance, prevention, and reversal of learned helplessness behavior. Using the technique of in vivo microdialysis, we measured the efflux of serotonin (5-HT), dopamine (DA), and their respective metabolites, 5-hydroxyindoleacetic acid (5-HIAA) and 3,4- dihydroxyphenylacetic acid (DOPAC), from the lateral septum of rats that either developed or did not develop learned helplessness. During the microdialysis session all rats were subjected to restraint stress. Control groups included naive, home cage rats as well as tested control rats that were subjected to the identical handling, restraint, and shuttlebox testing as the rats that received inescapable shock. Overall, levels of 5-HIAA were significantly higher in non-helpless rats. There were no significant effects of restraint or differences in levels of 5-HT, DA, or DOPAC. We propose that this increase in 5-HIAA is indicative of an overall increase in serotonin metabolism in the lateral septum of rats that do not become helpless after inescapable stress. This increased serotonin metabolism in the lateral septum may protect the animal from adverse behavioral consequences of inescapable stress.
KW - 5-HIAA
KW - Depression
KW - Immobilization
KW - Lateral septum
KW - Learned helplessness
KW - Microdialysis
KW - Restraint
KW - Serotonin
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U2 - 10.1002/1097-4547(20000701)61:1<101::AID-JNR12>3.0.CO;2-S
DO - 10.1002/1097-4547(20000701)61:1<101::AID-JNR12>3.0.CO;2-S
M3 - Article
C2 - 10861805
AN - SCOPUS:0034235718
SN - 0360-4012
VL - 61
SP - 101
EP - 106
JO - Journal of Neuroscience Research
JF - Journal of Neuroscience Research
IS - 1
ER -