It has been proposed that analgesia in the formalin test is mediated through forebrain systems associated with reinforcement, whereas motor responses necessary for the expression of pain are organized at the level of the brainstem. Because it is located in the brainstem and connected with both limbic reward systems and motor structures, the pedunculopontine tegmental nucleus (PPTg) is a site where reward signals might influence the expression of pain. Experiment 1 confirmed that NMDA-induced lesions of the PPTg block the development of a conditioned place preference to morphine. Subsequently, morphine-induced analgesia was found to be reduced, but not eliminated. The reduction of reward was not significantly correlated with loss of choline acetyltransferase containing neurons in the PPTg. In Experiment 2, PPTg lesions did not affect morphine analgesia in drug naive animals, but produced motor abnormalities and blocked the morphine-induced depression of spontaneous motor activity and catalepsy.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.61087 |
| Date | January 1991 |
| Creators | Olmstead, Mary C. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Psychology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001275151, proquestno: AAIMM74687, Theses scanned by UMI/ProQuest. |
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