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

Olfactory associative learning was used to investigate the involvement of K y channels containing Kv1.1 and Kv1.3 alpha -subunits in learning and memor y. Kaliotoxin (KTX), a specific inhibitor of these Ky channels, was injecte d intracerebroventricularly in the rat brain, at a dose of 10 ng that did n ot disturb the rats' locomotor activity or drinking behaviour. In the first paradigm (odour-reward training), KTX improved learning but not informatio n consolidation. Moreover, KTX increased the long-term retrieval of an odou r-reward association tested by a reversal test 1 month after the odour-rewa rd training. The second paradigm (successive odour-pair training) tested re ference memory. The first session was an acquisition session where the rats learned a new odour-discrimination problem with the same procedure. The se cond was a retention session held 24 h later to test retrieval of the learn ed information. KTX injected before the acquisition or retention session im proved performance, but no effect was found when KTX was injected immediate ly after acquisition. We showed that these effects were not due to the acti on of KTX on attention processes. Thus, these results suggest that the bloc kage of Kv1.1 or Kv1.3 channels by KTX facilitates cognitive processes as l earning, in particular in a reference representation. (C) 2001 Elsevier Sci ence B.V. All rights reserved.