Basolateral amygdala stimulation does not recruit LTP at depotentiated synapses.
Hippocampal long-term potentiation (LTP) is a long-lasting increase in synaptic efficacy considered to be the cellular basis of memory. LTP consists of an early, protein synthesis-independent phase (E-LTP) and a late phase that depends on protein synthesis (L-LTP). Application of a weak tetanus can induce E-LTP in the dentate gyrus (DG) which can be reinforced into L-LTP by direct stimulation of the basolateral amygdala (BLA) within 30 min before or after LTP induction (structural LTP-reinforcement). LTP can be depotentiated by low-frequency stimulation (LFS) to the same synaptic input if applied shortly after tetanization (<10 min). Here, we addressed the question of whether stimulation of the BLA is able to recover LTP at depotentiated synaptic inputs. We hypothesized that E-LTP can activate synaptic tags, which were then reset by depotentiation. Stimulation of the BLA thereafter could beneficially act on tag-reactivation as well as on the activation of the synthesis of plasticity-related proteins (PRPs), normally captured by the tags and thus transforming E-LTP into L-LTP. Our results show, that BLA-stimulation was not able to reactivate the resetting of tags by depotentiation in the DG of freely moving rats.
Almaguer-Melian
W
W
International Centro for Neurological Restoration (CIREN), 11300 Havana, Cuba.
Bergado
J A
JA
Martínez-Martí
L
L
Duany-Machado
C
C
Frey
J U
JU
D000679:Amygdala / Q000502:physiology*; D000818:Animals; D018891:Dentate Gyrus / Q000502:physiology*; D004558:Electric Stimulation; D017774:Long-Term Potentiation / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000502:physiology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012032:Refractory Period, Electrophysiological / Q000502:physiology; D013569:Synapses / Q000502:physiology*