Lidocaine, tetrodotoxin and their effect on consolidation of spatial memory.
This study was aimed at comparing the effect of unilateral hippocampal inactivation with tetrodotoxin (TTX) and lidocaine on spatial memory consolidation. Both drugs block voltage-dependent sodium channels. However, TTX and lidocaine differ in the duration of their effects, with maximum TTX effect between 30 min and 120 min, washing out in 24 hours. Lidocaine maximum effect occurs 20-30 minutes after administration. Our experimental subjects, twenty-four 3-month-old Wistar rats, were unilaterally implanted with stainless-steel cannulae aimed at the right dorsal hippocampus. Animals received four daily trials for 5 consecutive days. Control injections of 1 microl saline, or inactivating injections of 5 ng of TTX in 1 microl saline or lidocaine (2%) in 1 microl were made through a guide cannula 1 minute after the last trial from day 1 to day 4. Results showed that the groups that received TTX or lidocaine did not differ but were impaired regarding controls, suggesting that short-term consolidation processes can account for the memory impairment observed here.
Cimadevilla
José Manuel
JM
Universidad de Almería, Facultad de Psicología, Almería, Spain.
López
Francisco
F
Nieto
Luz
L
Aguirre
Ma Jesús
MJ
Fernández
Rubén
R
D000818:Animals; D008012:Lidocaine / Q000009:adverse effects / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects*; D008569:Memory Disorders / Q000139:chemically induced; D051381:Rats; D017208:Rats, Wistar; D026941:Sodium Channel Blockers / Q000009:adverse effects / Q000494:pharmacology*; D013779:Tetrodotoxin / Q000009:adverse effects / Q000494:pharmacology*
D026941:Sodium Channel Blockers; D013779:Tetrodotoxin; D008012:Lidocaine