Differential effects of two blockers of small conductance Ca2+-activated K+ channels, apamin and lei-Dab7, on learning and memory in rats.
SK channels are responsible for long-lasting hyperpolarization following action potential and contribute to the neuronal integration signal. This study evaluates the involvement of SK channels on learning and memory in rats, by comparing the effects of two SK channel blockers, i.e., apamin which recognizes SK2 and SK3 channels, and lei-Dab7 which binds SK2 channels only. lei-Dab7 totally competes and contests apamin binding on whole brain sections (IC(50): 11.4 nM). Using an olfactory associative task, intracerebroventricular blocker injections were tested on reference memory. Once the task was mastered with one odor pair, it was then tested with a new odor pair. Apamin (0.3 ng), injected before or after the acquisition session, improved new odor pair learning in a retention session 24 hours later, whereas lei-Dab7 (3 ng) did not significantly affect the mnesic processes. These results indicated that the blockage of SK channels by apamin facilitates consolidation on new odor associations; lei-Dab7, containing only SK2 subunits, remains without effect suggesting an involvement of SK3 channels in the modulation of the mnesic processes.
Mpari
Bedel
B
Laboratoire de Neurobiologie Intégrative et Adaptative, Neurobiologie des Processus Mnésiques, UMR 6149, CNRS-Université de Provence, Marseille, France.
Regaya
Imed
I
Escoffier
Guy
G
Mourre
Christiane
C
D000704:Analysis of Variance; D000818:Animals; D001030:Apamin / Q000493:pharmacokinetics / Q000494:pharmacology*; D001245:Association Learning / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects; D001667:Binding, Competitive / Q000187:drug effects; D004193:Discrimination Learning / Q000187:drug effects*; D007456:Iodine Isotopes / Q000493:pharmacokinetics; D008297:Male; D008568:Memory / Q000187:drug effects*; D009812:Odorants; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects; D012153:Retention, Psychology / Q000187:drug effects; D012604:Scorpion Venoms / Q000494:pharmacology*; D051640:Small-Conductance Calcium-Activated Potassium Channels / Q000037:antagonists & inhibitors*
D007456:Iodine Isotopes; D012604:Scorpion Venoms; D051640:Small-Conductance Calcium-Activated Potassium Channels; C442227:diaminobutanoyl(7)-leiurotoxin I; D001030:Apamin