Effects of chemotherapeutic agents 5-fluorouracil and methotrexate alone and combined in a mouse model of learning and memory
- 8 May 2008
- journal article
- research article
- Published by Springer Science and Business Media LLC in Psychopharmacology
- Vol. 199 (4), 527-538
- https://doi.org/10.1007/s00213-008-1175-y
Abstract
Rationale The concern that adjuvant cancer chemotherapy agents cause cognitive impairment in a significant number of patients has been expressed by patients and healthcare providers, but clinical studies have yielded conflicting results to date. Objective We directly tested two commonly used chemotherapeutic agents in a mouse model of learning and memory. Materials and methods In the present study, mice were conditioned to respond for a liquid reinforcer (Ensure solution) in the presence of an audible tone on day 1 as a measure of acquisition and were then required to perform the same response on day 2 as a measure of retrieval and retention. Methotrexate and 5-fluorouracil were administered prior to the day 1 session. Results Methotrexate (1.0–32 mg/kg) alone failed to alter mean latency acquisition, retrieval, or reinforced response rates. Similar to scopolamine, a known amnesic in this assay, 5-fluorouracil (3-75 mg/kg) failed to alter response rates or acquisition latency on day 1 but significantly altered latency to retrieve a previously learned response on day 2. In combination, 3.2 mg/kg methotrexate plus 75 mg/kg 5-fluorouracil significantly increased day 1 and day 2 acquisition and retrieval latencies without altering response rates or motivation to respond as measured by progressive ratio responding. Conclusion Taken together, these data demonstrate that 5-fluorouracil causes increased latencies for retrieval of previously learned behavioral responses and that combination of chemotherapeutic agents may produce greater delays than either agent alone, including when neither agent alone does so.Keywords
This publication has 58 references indexed in Scilit:
- Clarification Regarding “Phase II Trials Published in 2002: A Cross-Specialty Comparison Showing Significant Design Differences between Oncology Trials and Other Medical Specialties” and the Accompanying Commentary, “Phase II Cancer Trials: Out of Control?”Clinical Cancer Research, 2007
- Candidate mechanisms for chemotherapy-induced cognitive changesNature Reviews Cancer, 2007
- Altered frontocortical, cerebellar, and basal ganglia activity in adjuvant-treated breast cancer survivors 5–10 years after chemotherapyBreast Cancer Research and Treatment, 2006
- Older adults with cognitive complaints show brain atrophy similar to that of amnestic MCINeurology, 2006
- Does neoadjuvant hormone therapy for early prostate cancer affect cognition? Results from a pilot studyBJU International, 2005
- Pharmacokinetics and tissue distribution of 5-fluorouracil encapsulated by galactosylceramide liposomes in mice1Acta Pharmacologica Sinica, 2005
- Plasma, Intestine and Tumor Levels of 5-Fluorouracil in Mice Bearing L1210 Ascites Tumor Following Oral Administration of 5-Fluorouracil, UFT (Mixed Compound of Tegafur and Uracil), Carmofur and 5'-Deoxy-5-fluorouridine.Biological & Pharmaceutical Bulletin, 2001
- Effects of scopolamine and hippocampal lesions on negative patterning discrimination performance in rats.Behavioral Neuroscience, 1997
- Effects of scopolamine and hippocampal lesions on negative patterning discrimination performance in rats.Behavioral Neuroscience, 1997
- Methotrexate does not interfere with an appetitive Pavlovian conditioning task in Sprague-Dawley ratsPhysiology & Behavior, 1995