Enhanced inhibitory avoidance learning prevents the memory-impairing effects of post-training hippocampal inactivation.
Rats were trained on an inhibitory avoidance task to study the effects of post-training administration of tetrodotoxin (TTX, which temporarily inactivates neural activity) on memory consolidation. During training, independent groups of rats received either a mild foot shock (0.8 mA) or a stronger (1.0 mA) foot shock. TTX was administered bilaterally into the dorsal hippocampus immediately after training, and memory of the task was measured 48 h later. We corroborated the typical amnesic effect of intrahippocampal infusions of TTX in those rats trained with the mild-intensity foot shock. More importantly, with the stronger foot shock, the same treatment was ineffective in producing amnesia. These results suggest that, after an enhanced learning experience, other brain regions are also activated, which may compensate for the amnesic effect of TTX infusions into the hippocampus.
Quiroz
César
C
Instituto de Neurobiología, Universidad Nacional Autónoma de México, PO Box 70-228, 04510 Mexico D.F., Mexico.
Martínez
Isabel
I
Quirarte
Gina L
GL
Morales
Teresa
T
Díaz-Cintra
Sofía
S
Prado-Alcalá
Roberto A
RA
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D008569:Memory Disorders / Q000139:chemically induced / Q000503:physiopathology*; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D016760:Proto-Oncogene Proteins c-fos; D013779:Tetrodotoxin; D007608:Kainic Acid