GABAergic Transmission in the Basolateral Amygdala Differentially Modulates Plasticity in the Dentate Gyrus and the CA1 Areas.
The term "metaplasticity" is used to describe changes in synaptic plasticity sensitivity following an electrical, biochemical, or behavioral priming stimulus. For example, priming the basolateral amygdala (BLA) enhances long-term potentiation (LTP) in the dentate gyrus (DG) but decreases LTP in the CA1. However, the mechanisms underlying these metaplastic effects are only partly understood. Here, we examined whether the mechanism underlying these effects of BLA priming involves intra-BLA GABAergic neurotransmission. Low doses of muscimol, a GABAA receptor (GABAAR) agonist, were microinfused into the rat BLA before or after BLA priming. Our findings show that BLA GABAAR activation via muscimol mimicked the previously reported effects of electrical BLA priming on LTP in the perforant path and the ventral hippocampal commissure-CA1 pathways, decreasing CA1 LTP and increasing DG LTP. Furthermore, muscimol application before or after tetanic stimulation of the ventral hippocampal commissure-CA1 pathways attenuated the BLA priming-induced decrease in CA1 LTP. In contrast, muscimol application after tetanic stimulation of the perforant path attenuated the BLA priming-induced increase in DG LTP. The data indicate that GABAAR activation mediates metaplastic effects of the BLA on plasticity in the CA1 and the DG, but that the same GABAAR activation induces an intra-BLA form of metaplasticity, which alters the way BLA priming may modulate plasticity in other brain regions. These results emphasize the need for developing a dynamic model of BLA modulation of plasticity, a model that may better capture processes underlying memory alterations associated with emotional arousing or stressful events.
['Vouimba|Rose-Marie|RM|', 'Anunu|Rachel|R|', 'Richter-Levin|Gal|G|']
D000818:Animals D066272:Basolateral Nuclear Complex D056547:CA1 Region, Hippocampal D018891:Dentate Gyrus D004566:Electrodes D017774:Long-Term Potentiation D008297:Male D009118:Muscimol D009473:Neuronal Plasticity D019580:Perforant Pathway D017207:Rats, Sprague-Dawley D009435:Synaptic Transmission D005680:gamma-Aminobutyric Acid
basolateral amygdala dentate gyrus CA1 metaplasticity synaptic plasticity GABA