TY - JOUR
T1 - Bidirectional synaptic plasticity in the rat basolateral amygdala
T2 - Characterization of an activity-dependent switch sensitive to the presynaptic metabotropic glutamate receptor antagonist 2S-α-ethylglutamic acid
AU - Li, He
AU - Weiss, Susan R B
AU - Chuang, De Maw
AU - Post, Robert M.
AU - Rogawski, Michael A
PY - 1998/3/1
Y1 - 1998/3/1
N2 - This study examines forms of activity-dependent synaptic plasticity in the basolateral amygdala in vitro and demonstrates that a brief high frequency stimulus (HFS) train can induce a switch in the direction of the enduring change in synaptic strength induced by subsequent low-frequency stimulation (LFS). LFS (1 Hz, 15 min) of the external capsule (EC) induced a persistent 1.7-fold enhancement in the amplitude of synaptic potentials recorded intracellularly in basolateral amygdala neurons. The enhancement occurred gradually during the stimulation and was maintained for >30 min after termination of the stimulus train. LFS-induced enduring synaptic facilitation was not affected by the NMDA receptor antagonist D(-)2-amino-5- phosphonopentanoate (APV; 100 μM). Brief high-frequency EC stimulation (HFS; 100 Hz, 1 sec) induced APV-sensitive short-term potentiation (2.5-fold) that generally decayed within 10 min. When LFS was applied after recovery from the short-term potentiating effect of HFS (HFS/LFS), there was an initial transient (<10 min) enhancement of the synaptic response followed by persistent synaptic depression (synaptic potential amplitude reduced by 22% at 30 min). This represents the first demonstration of stimulus-dependent long-lasting synaptic depression in the amygdala. Application of the presynaptic (group II) metabotropic glutamate receptor antagonist 2S-α- ethylglutamic acid (EGLU; 50 μM) prevented the HFS-dependent switch from synaptic facilitation to depression. Thus, LFS in the in vitro amygdala slice can induce either enduring synaptic potentiation or depression, depending on whether a priming HFS train has been applied. This experience-dependent switch, a novel form of metaplasticity, is not dependent on NMDA receptors but may require group II metabotropic glutamate receptors. In the amygdala, experiential modification of activity-dependent long-term synaptic plasticity adds flexibility to the ways in which synaptic strength can be modified and could play a role in diverse amygdala-dependent processes, including the formation, storage, and extinction of emotional memory and the regulation of epileptogenesis.
AB - This study examines forms of activity-dependent synaptic plasticity in the basolateral amygdala in vitro and demonstrates that a brief high frequency stimulus (HFS) train can induce a switch in the direction of the enduring change in synaptic strength induced by subsequent low-frequency stimulation (LFS). LFS (1 Hz, 15 min) of the external capsule (EC) induced a persistent 1.7-fold enhancement in the amplitude of synaptic potentials recorded intracellularly in basolateral amygdala neurons. The enhancement occurred gradually during the stimulation and was maintained for >30 min after termination of the stimulus train. LFS-induced enduring synaptic facilitation was not affected by the NMDA receptor antagonist D(-)2-amino-5- phosphonopentanoate (APV; 100 μM). Brief high-frequency EC stimulation (HFS; 100 Hz, 1 sec) induced APV-sensitive short-term potentiation (2.5-fold) that generally decayed within 10 min. When LFS was applied after recovery from the short-term potentiating effect of HFS (HFS/LFS), there was an initial transient (<10 min) enhancement of the synaptic response followed by persistent synaptic depression (synaptic potential amplitude reduced by 22% at 30 min). This represents the first demonstration of stimulus-dependent long-lasting synaptic depression in the amygdala. Application of the presynaptic (group II) metabotropic glutamate receptor antagonist 2S-α- ethylglutamic acid (EGLU; 50 μM) prevented the HFS-dependent switch from synaptic facilitation to depression. Thus, LFS in the in vitro amygdala slice can induce either enduring synaptic potentiation or depression, depending on whether a priming HFS train has been applied. This experience-dependent switch, a novel form of metaplasticity, is not dependent on NMDA receptors but may require group II metabotropic glutamate receptors. In the amygdala, experiential modification of activity-dependent long-term synaptic plasticity adds flexibility to the ways in which synaptic strength can be modified and could play a role in diverse amygdala-dependent processes, including the formation, storage, and extinction of emotional memory and the regulation of epileptogenesis.
KW - 2S-α- ethylglutamic acid
KW - Basolateral amygdala
KW - Long- term depression
KW - Long-term potentiation
KW - Metabotropic glutamate receptor
KW - NMDA receptor
KW - Synaptic plasticity
UR - http://www.scopus.com/inward/record.url?scp=0032031663&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032031663&partnerID=8YFLogxK
M3 - Article
C2 - 9464991
AN - SCOPUS:0032031663
VL - 18
SP - 1662
EP - 1670
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 5
ER -