Date of Award

12-1-1994

Degree Type

Restricted Access Thesis

Degree Name

Master of Science

Field of Study

Pharmacology and Neuroscience

Department

Graduate School of Biomedical Sciences

First Advisor

Michael W. Emmett-Oglesby

Second Advisor

Thomas Yorio

Abstract

Marianna Eunsun, Jung, Discriminative and Negative Reinforcing Properties of Electrical brain stimulation of the Periaqueductal Gray and the Medial Hypothalamus. Master of Science [Biomedical Sciences, (Pharmacology)], December, 1994, 123 pp., 24 figures, references, 137 titles. Electrical brain stimulation (EBS) of the periaqueductal gray (PAG) and the medial hypothalamus (MH) is known to serve as a discriminative and a negative reinforcing stimulus (NRS). Using a two-lever food reinforced discrimination paradigm and a switch-off paradigm, the present study investigated the effects of anxiolytic drugs and an anxiogenic drug on these stimulus effects. A prototypic anxiogenic, pentylenetetrazole (PTZ) potentiated both discriminative stimulus and NRS effects, whereas the full benzodiazepine (BZD) agonist diazepam (DZP), the partial BZD agonist abecarnil (ABC) and 5-HT1A agonist buspirone (BUS, chronic regimen) attenuated a NRS effect. A BZD antagonist, flumazenil (FLU) blocked the effects of DZP and ABC on the NRS effects. DZP failed to attenuate the discriminative stimulus effect. Thus, present study extended the use of a switch-off paradigm to detect novel anxiolytic ABC (putative) and BUX as well as an anxiogenic PTZ. In addition, under the condition used in this study, the use of NRS in a switch-off paradigm more reliably detected both anxiolytic drugs and an anxiogenic drug than the use of discriminative stimulus in a two-lever food reinforced paradigm.

Comments

Marianna Eunsun, Jung, Discriminative and Negative Reinforcing Properties of Electrical brain stimulation of the Periaqueductal Gray and the Medial Hypothalamus. Master of Science [Biomedical Sciences, (Pharmacology)], December, 1994, 123 pp., 24 figures, references, 137 titles. W 4.5 J95D 1994

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