The effects of developmental lead exposure on cocaine-induced behaviors /
Developmental exposure to lead has been demonstrated to produce changes in the neural mechanisms of drug reward. The experiments presented the effects of perinatal lead exposure on cocaine-induced changes in behavior in rats. Adult female rats were garaged daily with 0, 8, or 16 mg lead acetate for...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1999.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=730298281&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Developmental exposure to lead has been demonstrated to produce changes in the neural mechanisms of drug reward. The experiments presented the effects of perinatal lead exposure on cocaine-induced changes in behavior in rats. Adult female rats were garaged daily with 0, 8, or 16 mg lead acetate for 30 days before breeding. This exposure regimen was maintained throughout gestation and lactation. On Day 21, male pups were weaned and lead exposure was discontinued for the remainder of the study. In Experiment 1, at post-natal day (PND) 30 and PND 90 pups were presented with 10 mg/kg cocaine and tested for locomotor activity for 14 consecutive days. Following this testing period, dose-effect profiles were determined. At both PND 30 and 90, lead-exposed animals were less sensitive to the initial administration of cocaine, but exhibited a supersensitivity to the effects of repeated drug presentation (sensitization). In Experiment 2, pups were trained with cocaine in a conditioned place preference (CPP) procedure at PND 30 and 90. At both PND 30 and 90, an attenuation in CPP was present in animals exposed to 8 or 16 mg lead relative to control rats. A conditioned place aversion procedure with lithium chloride determined no differences among pups from each exposure group, suggesting an impairment of associative processing was not solely responsible for the attenuation in cocaine CPP. In Experiment 3, animals were trained to discriminate between saline and 5 mg/Kg cocaine injections with training commencing on PND 45. After acquisition training, significant lead-exposure group differences were present on generalization tests with SKF 38393 (preferential D1 agonist) and quinpirole (preferential D2 agonist). In Experiment 4, pups received a high-dose injection of cocaine at PND 30 or 90 and were observed for onset of seizures and death. No differences were present among lead exposure groups relative to controls. Analysis of blood-lead data revealed that lead levels were below detectable limits for all animals. Collectively, these findings show that developmental lead contamination produces changes in cocaine sensitivity long after exposure has been discontinued and the toxicant has gained clearance from blood. |
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| Item Description: | Vita. "Major Subject: Psychology". |
| Physical Description: | viii, 114 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 101-113). |