ADULT and aged mice were submitted to a discrimination task in a radial maze (regular trials), and then to probe trials requiring them to form relational representations. Three weeks later, animals were again tested for regular and probe trials. Following another interval of 3 weeks, individual hippocampal cytosolic calcium-dependent and -independent PKC activities were measured. Performance of aged animals was impaired on probe but not regular trials and aged mice had lower hippocampal cytosolic calcium-dependent and -independent PKC activities than adults. Performance on probe trials was specifically correlated with calcium-dependent PKC activity. This suggests a specific relationship between the ability to form relational representations and hippocampal cytosolic calcium-dependent PKC activity.
1Institute of Pharmacological Sciences, University of Milano, Italy
2Laboratoire de Neurosciences Comportementales et Cognitives, UMR CNRS 5807, Université de Bordeaux I, Avenue des Facultés, 33405 Talence Cedex, France
3Department of Experimental Medicine and Biochemical Sciences, University of Roma, Tor Vergata, Roma
4Institute of Pharmacology, University of Pavia, Italy
5Corresponding Author: Xavier Noguès
ACKNOWLEDGEMENTS: We wish to thank Dr Ray Cook for linguistic corrections. This study was supported by URA CNRS 339, University of Bordeaux I and the Institute of Pharmacological Sciences, University of Milano.
Received 16 October 1997; accepted 21 December 1997
Website publication 17 February 1998