Changes in sensitivity of response distributions to changing reinforcement ratios during exposure to ephedrine, caffeine, and ephedrine–caffeine combinations
| Autor: | Yuliya Borre, James D. Dougan, Valeri Farmer-Dougan, Byron A. Heidenreich, Seshanand P. Chandrashekar |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Male
Drug Reinforcement Schedule media_common.quotation_subject Self Administration Pharmacology Sensitivity and Specificity Rats Sprague-Dawley chemistry.chemical_compound Reward Caffeine medicine Animals Distribution (pharmacology) Ephedrine Reinforcement media_common Analysis of Variance Behavior Animal Dose-Response Relationship Drug Differential effects Rats Drug Combinations Psychiatry and Mental health chemistry Anesthesia Conditioning Operant Central Nervous System Stimulants Analysis of variance Self-administration Reinforcement Psychology medicine.drug |
| Zdroj: | Behavioural Pharmacology. 18:609-622 |
| ISSN: | 0955-8810 |
| DOI: | 10.1097/fbp.0b013e3282f14eab |
| Popis: | Changes in the sensitivity of response distributions to changes in reward distribution (reinforcer distribution sensitivity) were examined when rats were exposed to low and moderate doses of caffeine, ephedrine, and caffeine-ephedrine combinations. The data show significant decreases in sensitivity in response distributions to changes in reward schedule values during exposure to caffeine and ephedrine/caffeine combinations, whereas ephedrine alone resulted in overmatching comparable with baseline and NaCl conditions. Rats treated either with 3.0-mg/kg or 10.0-mg/kg doses of caffeine and all combinations of ephedrine at doses of 1.8 or 5.6 mg/kg with caffeine at 3.0 or 10.0 mg/kg showed reduced sensitivity in response distributions to differences in reinforcement schedule ratios. In contrast, when rats were exposed to ephedrine at 1.8 or 5.6 mg/kg, they maintained or increased the degree of overmatching. Although reinforcer distribution sensitivity was altered, drug exposure did not significantly affect the absolute rates of responding. Bias varied after exposure to caffeine, ephedrine, and their combinations, but not systematically. Finally, whereas the estimates of goodness of fit (r2) to the matching equation showed some decreases during drug exposure, these were neither statistically significant nor correlated with drug dose. These results suggest differential effects of ephedrine and caffeine on the sensitivity of response distributions to changes in reinforcement ratio distributions, with deleterious effects of caffeine and ephedrine/caffeine combinations. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|