Endogenous opioids: Naloxone disrupts learned performance in rats
| Autor: | Wesley C. Lynch, Sheldon Clark |
|---|---|
| Rok vydání: | 1983 |
| Předmět: |
Male
Run down medicine.medical_specialty Enkephalin Enkephalin Methionine medicine.medical_treatment Motor Activity General Biochemistry Genetics and Molecular Biology Internal medicine Naloxone Male rats D-Ala(2) MePhe(4) Met(0)-ol-enkephalin medicine Animals Humans Learning General Pharmacology Toxicology and Pharmaceutics Saline Endogenous opioid Depression business.industry Rats Inbred Strains General Medicine Hormones Rats Disease Models Animal Endocrinology Anesthesia Opiate business Reinforcement Psychology medicine.drug |
| Zdroj: | Life Sciences. 32:2801-2807 |
| ISSN: | 0024-3205 |
| DOI: | 10.1016/0024-3205(83)90402-2 |
| Popis: | The effect of naloxone on learned performance reinforced by food was examined in 2 experiments. Male rats were trained to run down a short runway for 5 (45 mg) food pellets per trial and were then shifted either to 1 or 0 pellets. Following such an abrupt reinforcement shift, animals typically show an emotional disruption of performance (Crespi, 1942) referred to as “depression.” We examined the postshift depression-effect in groups treated either with saline (SAL) or naloxone (NAL). In experiment 1 NAL groups received a single 10 mg/kg (s.c.) injection prior to each postshift session. When compared with SAL controls, NAL animals showed an exaggerated postshift depression-effect. Furthermore, a single (0.3 mg/kg, s.c.) injection of the enkephalin analog FK 33-824 (D-Ala 2 , MePhe 4 , Met-(0) 5 -o1) produced a dramatic recovery of performance. In the second experiment, these effects were replicated at a low NAL dose (1 mg/kg), which had no direct effect on motor performance. These findings suggest that opiate systems may modulate the incentive motivation that maintains learned performance. |
| Databáze: | OpenAIRE |
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