Modulation of working, short- and long-term memory by nicotinic receptors in the basolateral amygdala in rats.
Male Wistar rats were exposed to one-trial step-down inhibitory avoidance training using a 0.5 mA footshock. Through bilaterally implanted indwelling cannulae, they received bilateral 0.5 microL infusions of saline, mecamylamine (1.0 or 10.0 microg/side), or nicotine (0.6 or 3.0 microg/side) into the basolateral complex of the amygdaloid nucleus (BLA). Infusions were either 10 min before training (Experiment 1) or 4 min after training (Experiment 2). In Experiment 1, the animals were tested three times: first for working memory (WM) 5 s after training, then for short-term memory (STM) 90 min later, and finally for long-term memory (LTM) 24 h later. Mecamylamine depressed and nicotine enhanced WM, STM, and LTM. In Experiment 2, the treatments were given after WM was presumably over. Again, mecamylamine inhibited and nicotine enhanced STM and LTM. The results indicate that nAChRs in BLA participate in the regulation of WM formation and STM and LTM acquisition and consolidation.
Barros
Daniela Martí
DM
Departamento de Ciências Fisiológicas, Fundação Universidade Federal de Rio Grande, Rio Grande, RS, Brazil. barrosdm@yahoo.com.br
Ramirez
Maria Rosana
MR
Izquierdo
Ivan
I
D000679:Amygdala / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology*; D008570:Memory, Short-Term / Q000187:drug effects* / Q000502:physiology; D009538:Nicotine / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000502:physiology; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000502:physiology; D012153:Retention, Psychology / Q000187:drug effects* / Q000502:physiology
D018733:Nicotinic Antagonists; D011950:Receptors, Cholinergic; D011978:Receptors, Nicotinic; D008464:Mecamylamine; D009538:Nicotine