A NEUROPHARMACOLOGICAL ANALYSIS OF LEARNED HELPLESSNESS IN RAT (GENETICS).

Persistent Link:
http://hdl.handle.net/10150/184251
Title:
A NEUROPHARMACOLOGICAL ANALYSIS OF LEARNED HELPLESSNESS IN RAT (GENETICS).
Author:
Wieland, Douglas Scott
Issue Date:
1987
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The purpose of this research project was to look for a neuropharmacological correlate to the behavioral deficits seen in learned helplessness (LH). The fact that antidepressant drugs reverse the deficits seen in a helpless rat, strongly suggests that the deficit is due to some neurochemical imbalance. This imbalance could be due to either the uncontrollable stressor or genetically induced. The three experiments suggest that there are fundamental differences in the way the CNS of helpless-prone rats and helpless-resistant rats cope with unpredictable and inescapable footshock. The goal of Experiment I was to search for a correlation between LH and receptor changes in the frontal cortex. The results did not support the hypothesis. The use of a heterogeneous stock of rat may have masked any basic differences between helpless-prone and helpless-resistant rats with regard to the 5-HT₂ and β-adrenergic receptors in the frontal cortex. Based on previous studies and the results from Experiment I, one could argue that there exists a genetic component in LH. The results from Experiment II suggest a strong genetic component to LH, not unlike that found in certain forms of human depressive disorders. Accordingly, rats from eight different stocks were tested for susceptibility to LH training. Of the eight stocks tested, Kyoto and Charles River Holtzman rats were the most susceptible at 53% and 55%, respectively. Overall, the variability ranged from 0% to 50%. These results indicate that wide differences in susceptibility to LH training exist in rats from different stocks or suppliers. The results of Experiment II suggested that the Kyoto Wistar rat would be a reliable inbred strain in which to study LH. With regards to the original goal of this research, it was decided that an evaluation of different neuro-transmitter systems during the LH paradigm would yield a potential for success in finding a biochemical marker that would differentiate LH-prone from LH-resistant rats. The results of Experiment III suggest, at least in hippocampus, that the serotonin (5-HT) and norepinephrine (NE) systems are differentially affected in the LH-prone and LH-resistant rat. In particular 5-HT levels are not affected by stress alone, but are increased in LH-prone rats following a frustrating test session. Also, the NE metabolite MHPG, is not affected by stress, but does increase in the LH-prone rat following testing. Both of these results differentiate the LH-prone and LH-resistant rat. In conclusion, the three experiments suggest that there is a genetic component in LH and that the NE and 5-HT systems are differentially affected by uncontrollable and inescapable shock in LH-prone and LH-resistant rats.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Helplessness (Psychology); Depression, Mental.; Antidepressants.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Psychology; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Hsiao, Sigmund

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleA NEUROPHARMACOLOGICAL ANALYSIS OF LEARNED HELPLESSNESS IN RAT (GENETICS).en_US
dc.creatorWieland, Douglas Scotten_US
dc.contributor.authorWieland, Douglas Scotten_US
dc.date.issued1987en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe purpose of this research project was to look for a neuropharmacological correlate to the behavioral deficits seen in learned helplessness (LH). The fact that antidepressant drugs reverse the deficits seen in a helpless rat, strongly suggests that the deficit is due to some neurochemical imbalance. This imbalance could be due to either the uncontrollable stressor or genetically induced. The three experiments suggest that there are fundamental differences in the way the CNS of helpless-prone rats and helpless-resistant rats cope with unpredictable and inescapable footshock. The goal of Experiment I was to search for a correlation between LH and receptor changes in the frontal cortex. The results did not support the hypothesis. The use of a heterogeneous stock of rat may have masked any basic differences between helpless-prone and helpless-resistant rats with regard to the 5-HT₂ and β-adrenergic receptors in the frontal cortex. Based on previous studies and the results from Experiment I, one could argue that there exists a genetic component in LH. The results from Experiment II suggest a strong genetic component to LH, not unlike that found in certain forms of human depressive disorders. Accordingly, rats from eight different stocks were tested for susceptibility to LH training. Of the eight stocks tested, Kyoto and Charles River Holtzman rats were the most susceptible at 53% and 55%, respectively. Overall, the variability ranged from 0% to 50%. These results indicate that wide differences in susceptibility to LH training exist in rats from different stocks or suppliers. The results of Experiment II suggested that the Kyoto Wistar rat would be a reliable inbred strain in which to study LH. With regards to the original goal of this research, it was decided that an evaluation of different neuro-transmitter systems during the LH paradigm would yield a potential for success in finding a biochemical marker that would differentiate LH-prone from LH-resistant rats. The results of Experiment III suggest, at least in hippocampus, that the serotonin (5-HT) and norepinephrine (NE) systems are differentially affected in the LH-prone and LH-resistant rat. In particular 5-HT levels are not affected by stress alone, but are increased in LH-prone rats following a frustrating test session. Also, the NE metabolite MHPG, is not affected by stress, but does increase in the LH-prone rat following testing. Both of these results differentiate the LH-prone and LH-resistant rat. In conclusion, the three experiments suggest that there is a genetic component in LH and that the NE and 5-HT systems are differentially affected by uncontrollable and inescapable shock in LH-prone and LH-resistant rats.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectHelplessness (Psychology)en_US
dc.subjectDepression, Mental.en_US
dc.subjectAntidepressants.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePsychologyen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorHsiao, Sigmunden_US
dc.contributor.committeememberConsroe, Paulen_US
dc.contributor.committeememberArkowitz, Harold S.en_US
dc.contributor.committeememberKing, Jimen_US
dc.identifier.proquest8803268en_US
dc.identifier.oclc700054213en_US
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