Time-dependent disruption of passive avoidance acquisition by post-training intra-amygdala injection of tetrodotoxin in rats.
The role of the amygdala (AM) in the consolidation of the passive avoidance reaction (PAR) has been examined with the tetrodotoxin (TTX)-induced functional block of this structure. Rats were trained in the step-through PAR and anesthetized with ketamine. TTX injected immediately after acquisition into both AM (2 x 10 ng) significantly reduced avoidance of the dark compartment in the retrieval test performed two days later. The amnesic effect was significant when the acquisition--TTX delay was prolonged to 90 min but not to 6 h or 24 h. Earlier research indicated that TTX blockade of the parabrachial nuclei caused similar PAR disruption when elicited 24 h but not 48 h after acquisition. Comparison of the TTX-induced retrograde amnesias indicates that the two structures play different roles in the formation of the PAR engram.
Bucherelli
C
C
Department of Physiological Sciences, University of Florence, Italy.
Tassoni
G
G
Bures
J
J
D000648:Amnesia, Retrograde / Q000139:chemically induced*; D000679:Amygdala / Q000187:drug effects*; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013779:Tetrodotoxin / Q000494:pharmacology*; D013997:Time Factors
D013779:Tetrodotoxin