LOCUS COERULEUS LESIONS DIFFERENTIALLY ALTERS MORPHINE'S EFFECTS ON HYPOTHALAMIC SELF-STIMULATION IN RATS.
Item
-
Title
-
LOCUS COERULEUS LESIONS DIFFERENTIALLY ALTERS MORPHINE'S EFFECTS ON HYPOTHALAMIC SELF-STIMULATION IN RATS.
-
Identifier
-
AAI8212218
-
identifier
-
8212218
-
Creator
-
TEMPEL, ANN.
-
Contributor
-
Steven J. Ellman
-
Date
-
1982
-
Language
-
English
-
Publisher
-
City University of New York.
-
Subject
-
Psychology, Physiological
-
Abstract
-
Studies have reported that morphine at low doses, facilitates some self-stimulation sites but not others. These sites are consistent with areas of high opiate receptor density. Farber (1976) showed that unilateral locus coeruleus lesions differentially altered ICSS rates. It was postulated that morphine exerts its effects on the reward system via the locus coeruleus. The following study explored the effects of morphine on ICSS from various sites before and after a discrete unilateral locus coeruleus lesion.;Rats were implanted with electrodes aimed at ICSS sites and were trained to bar press for brain stimulation. After rates stabilized, subjects entered the paradigm which consisted of 7 days saline, 1 day naloxone, 7 days saline, 7 days morphine, 1 day morphine + naloxone, 7 days saline, 1 day d-amphetamine, 2 days saline, 1 day L-amphetamine, 2 days saline, 1 day L-amphetamine, 2 days saline, 1 day d-amphetamine and 7 days saline. Animals were then anesthetized and acutely lesioned in the left coeruleus. The paradigm post-lesion was identical to the pre-lesion paradigm.;Locus coeruleus (LC) lesions reduced ICSS response rates in subjects whose electrodes were located in the H(,2)Fields of Forel (FF), Zona Incerta (ZI), Internal Capsule (IC), Mammillothalamic Tract (MT) and thalamic nuceli. ICSS in subjects whose hypothalamic electrodes were located in the Medial forebrain bundle (MFB)-Perifornical (PF) area were not affected by these lesions. Morphine facilitated ICSS rates from electrodes in the H(,2)FF, ZI, MT, thalamic nuclei and MFB-PF area. ICSS rates in the IC were not altered by morphine administration. Post-lesion ICSS rates from the H(,2)FF, ZI, MT and thalamic nuclei which were depressed following the lesion were facilitated to pre-lesion saline levels under morphine administration but not pre-lesion morphine levels. Post-lesion ICSS rates from the IC that were depressed following the LC lesion, were still not altered by morphine administration. Morphine administration produced comparable facilitations in ICSS rates in the MFB-PF area post-lesion, as it did pre-lesion. ICSS rates in this group were not altered by the LC lesion.;These results support the idea that there are several reward-ICSS systems and that these systems can be differentially affected by LC lesions and morphine administration.
-
Type
-
dissertation
-
Source
-
PQT Legacy CUNY.xlsx
-
degree
-
Ph.D.
-
Program
-
Psychology
