Kaliotoxin, a Kv1.1 and Kv1.3 channel blocker, improves associative learning in rats

Olfactory associative learning was used to investigate the involvement of Ky channels containing Kv1.1 and Kv1.3 alpha -subunits in learning and memory. Kaliotoxin (KTX), a specific inhibitor of these Ky channels, was injected intracerebroventricularly in the rat brain, at a dose of 10 ng that did not disturb the rats' locomotor activity or drinking behaviour. In the first paradigm (odour-reward training), KTX improved learning but not information consolidation. Moreover, KTX increased the long-term retrieval of an odour-reward association tested by a reversal test 1 month after the odour-reward training. The second paradigm (successive odour-pair training) tested reference memory. The first session was an acquisition session where the rats learned a new odour-discrimination problem with the same procedure. The second was a retention session held 24 h later to test retrieval of the learned information. KTX injected before the acquisition or retention session improved performance, but no effect was found when KTX was injected immediately after acquisition. We showed that these effects were not due to the action of KTX on attention processes. Thus, these results suggest that the blockage of Kv1.1 or Kv1.3 channels by KTX facilitates cognitive processes as learning, in particular in a reference representation. (C) 2001 Elsevier Science B.V. All rights reserved.