MOLINA VICTOR ALEJANDRO
Congresos y reuniones científicas
Título:
Modulation of fear conditioning by MK-801 in ethanol withdrawn rats
Autor/es:
BERTOTTO ME, BOIERO C, MOLINA VA, MARTIJENA ID
Lugar:
Tandil, Argentina
Reunión:
Congreso; XL Reunión anual de la Asociación Argentina de Farmacología; 2008
Institución organizadora:
Sociedad Argentina de Farmacología Experimental
Resumen:
We have recently shown that discontinuation from chronic ethanol
administration results in a clear enhancement of contextual fear
conditioning. It is known that NMDA receptors are a major site for
ETOH action and that they play a critical role in memory processes and
in associative aversive learning. Therefore, in the present study we
investigated the effect of MK-801, a NMDA receptor antagonist, on fear
conditioning in ETOH withdrawn rats.
Wistar rats made dependent via an etanol (6% v/v) containing liquid
diet for 14 days. Three days after the last ethanol administration
animals were injected with MK-801 (0.1 mg/kg i.p.) 30 min before a
contextual fear conditioning paradigm (3 electrical foot-shocks 0.4mA,
duration 3s; ITI: 30s). Twenty-four hours later animals were exposed
to the context without shock delivery and the freezing response was
evaluated.
The present study shows that: 1). The formation of a new fear memory
is facilitated in animals that have previously experienced ETOH
withdrawal. 2). Administration of MK-801, at a dose that did not
affect the acquisition of contextual fear conditioning in control
animals, normalized the freezing response in ETOH withdrawn rats. 3).
0.3 mg/kg seems to be an effective dose of MK-801 to block the fear
conditioning acquisition in control rats.
The enhanced sensitivity to the facilitatory effect of MK-801 in ETOH
withdrawn animals may be mediated by adaptive changes in NMDA
receptors provoked by ETOH dependence.
administration results in a clear enhancement of contextual fear
conditioning. It is known that NMDA receptors are a major site for
ETOH action and that they play a critical role in memory processes and
in associative aversive learning. Therefore, in the present study we
investigated the effect of MK-801, a NMDA receptor antagonist, on fear
conditioning in ETOH withdrawn rats.
Wistar rats made dependent via an etanol (6% v/v) containing liquid
diet for 14 days. Three days after the last ethanol administration
animals were injected with MK-801 (0.1 mg/kg i.p.) 30 min before a
contextual fear conditioning paradigm (3 electrical foot-shocks 0.4mA,
duration 3s; ITI: 30s). Twenty-four hours later animals were exposed
to the context without shock delivery and the freezing response was
evaluated.
The present study shows that: 1). The formation of a new fear memory
is facilitated in animals that have previously experienced ETOH
withdrawal. 2). Administration of MK-801, at a dose that did not
affect the acquisition of contextual fear conditioning in control
animals, normalized the freezing response in ETOH withdrawn rats. 3).
0.3 mg/kg seems to be an effective dose of MK-801 to block the fear
conditioning acquisition in control rats.
The enhanced sensitivity to the facilitatory effect of MK-801 in ETOH
withdrawn animals may be mediated by adaptive changes in NMDA
receptors provoked by ETOH dependence.
