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Eur J Neurosci. 2015 Jan;41(2):216-26. doi: 10.1111/ejn.12782. Epub 2014 Nov 13.

Increased adult hippocampal neurogenesis is not necessary for wheel running to abolish conditioned place preference for cocaine in mice.

Author information

1
Beckman Institute, University of Illinois at Urbana-Champaign, 405 North Mathews Avenue, Urbana, IL, 61801, USA; Neuroscience Program, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA.

Abstract

Recent evidence suggests that wheel running can abolish conditioned place preference (CPP) for cocaine in mice. Running significantly increases the number of new neurons in the hippocampus, and new neurons have been hypothesised to enhance plasticity and behavioral flexibility. Therefore, we tested the hypothesis that increased neurogenesis was necessary for exercise to abolish cocaine CPP. Male nestin-thymidine kinase transgenic mice were conditioned with cocaine, and then housed with or without running wheels for 32 days. Half of the mice were fed chow containing valganciclovir to induce apoptosis in newly divided neurons, and the other half were fed standard chow. For the first 10 days, mice received daily injections of bromodeoxyuridine (BrdU) to label dividing cells. On the last 4 days, mice were tested for CPP, and then euthanized for measurement of adult hippocampal neurogenesis by counting the number of BrdU-positive neurons in the dentate gyrus. Levels of running were similar in mice fed valganciclovir-containing chow and normal chow. Valganciclovir significantly reduced the numbers of neurons (BrdU-positive/NeuN-positive) in the dentate gyrus of both sedentary mice and runner mice. Valganciclovir-fed runner mice showed similar levels of neurogenesis as sedentary, normal-fed controls. However, valganciclovir-fed runner mice showed the same abolishment of CPP as runner mice with intact neurogenesis. The results demonstrate that elevated adult hippocampal neurogenesis resulting from running is not necessary for running to abolish cocaine CPP in mice.

KEYWORDS:

conditioned place preference; exercise; nestin; thymidine kinase; valganciclovir

PMID:
25393660
PMCID:
PMC4300275
DOI:
10.1111/ejn.12782
[Indexed for MEDLINE]
Free PMC Article

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