Long-Evans rats were used in experiments. Stimulating electrodes were implanted into perforanth path (PP) and ventral hippocampal commissure (VHC), recording ones – into dorsal dentate gyrus and CA1 hippocampal field respectively. Tetanic stimulation (theta-rhythm for PP and 100 Hz for VHC) was used to control LTP induction. System (intraperitoneal) or central (intraventricular) injections of sub-threshold doses of NMDA-r antagonists did not block LTP induction, but dramatically changed animal behavior. Hyperactivity with vestibular and motor deficits was observed in each animal after administration of NMDA-r antagonist in the home-cage. Spatial learning was examined in Morris watermaze. The control group of animals (NaCl injection) had no any behavioral deficits. On the contrary, experimental animals could not learn the task with underwater platform in spite of intact LTP induction. They also could not learn non-hippocampal task with a visible platform. This indicates that some sensory deficits also may take place after administration of NMDA-r antagonists. Our results do not support the hypothesis that NMDA-dependent LTP is required in spatial learning.
Grant support was provided by the Russian Foundation for Basic Research (10-04-01707-a). ВЛИЯНИЕ ПРОДОЛЖИТЕЛЬНОГО КОСМИЧЕСКОГО ПОЛЕТА НА СОКРАТИТЕЛЬНЫЕ СВОЙСТВА СКЕЛЕТНОЙ МЫШЦЫ ЧЕЛОВЕКА