Interleukin-18 regulates motor activity, anxiety and spatial learning without affecting synaptic plasticity.
Expression of Schaffer collateral-CA1 long-term potentiation (LTP) and long-term depression (LTD) was not affected in hippocampal slices from wild-type mice pretreated with lipopolysaccharide (0.25mg/kg, i.p.), to increase interleukin-18 (IL-18) concentrations in the brain. For IL-18 knock-out (IL-18 KO) mice, the LTP was still expressed, the extent being similar to that for wild-type mice. In the open-field test to assess motor activity, rearing activity for IL-18 KO mice was significantly suppressed as compared with that for wild-type mice, without significant difference in the locomotion activity between two groups. In the passive avoidance test to assess fear memory, the retention latency for IL-18 KO mice was much shorter than for wild-type mice, without significant difference in the acquisition latency between two groups. In the water maze test, the acquisition latency for IL-18 KO mice significantly prolonged as compared with that for wild-type mice, without significant difference in the retention latency between two groups. For IL-18 KO mice, intraventricular injection with IL-18 for 4 days (total, 240 fg) prior to water maze task shortened the prolonged acquisition latency, reaching a level similar to that for wild-type mice. The results of the present study, thus, suggest that IL-18 is a critical regulator for exploratory activity, fear memory, and spatial learning.
Yaguchi
Takahiro
T
Division of Bioinformation, Department of Physiology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya Hyogo 663-8501, Japan.
Nagata
Tetsu
T
Yang
Dongqin
D
Nishizaki
Tomoyuki
T
D000818:Animals; D001007:Anxiety / Q000503:physiopathology*; D001362:Avoidance Learning / Q000502:physiology; D001921:Brain / Q000502:physiology; D056547:CA1 Region, Hippocampal / Q000502:physiology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005106:Exploratory Behavior / Q000502:physiology; D007276:Injections, Intraventricular; D020382:Interleukin-18 / Q000008:administration & dosage / Q000235:genetics / Q000502:physiology*; D008070:Lipopolysaccharides; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009043:Motor Activity / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D013037:Spatial Behavior; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology
D020382:Interleukin-18; D008070:Lipopolysaccharides