TY - JOUR
T1 - Activity-dependent short-term enhancement of intercellular coupling
AU - Pereda, Alberto E.
AU - Faber, Donald S.
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 1996/2/1
Y1 - 1996/2/1
N2 - It was reported previously that repeated brief tetanization of the posterior eighth nerve can produce long-term homosynaptic potentiations of the electrotonic and chemical components of the mixed EPSP evoked in the Mauthner cell lateral dendrite by a single stimulus to the nerve. We show here that the same stimulus paradigm can lead, alternatively, to short-term enhancements of both excitatory responses. These transient modifications last for ~3 min, with a time course similar to post-tetanic potentiation at chemical synapses. However, a different stimulus pattern that transiently increases the presynaptic calcium concentration, paired-nerve stimuli, does not have any significant effect on electrotonic transmission, whereas it facilitates the chemically mediated EPSP. On the other hand, induction of the short-lasting potentiation of coupling, which depended on the discontinuous or burst-like property of the tetanizing paradigm, required NMDA-receptor activation and was blocked by postsynaptic intradendritic injections of the calcium chelator bis(2-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid. The ineffectiveness of presynaptic calcium in potentiating electrotonic coupling likely reflects the involvement of a calcium-dependent regulatory protein in the postsynaptic cell and suggests that hemichannels on the two aides of a gap junction plaque can be modified independently. NMDA-mediated modulation of gap junctions could be widespread, because both types of channels coexist during development and in several mammalian adult central nervous system structures such as hippocampus.
AB - It was reported previously that repeated brief tetanization of the posterior eighth nerve can produce long-term homosynaptic potentiations of the electrotonic and chemical components of the mixed EPSP evoked in the Mauthner cell lateral dendrite by a single stimulus to the nerve. We show here that the same stimulus paradigm can lead, alternatively, to short-term enhancements of both excitatory responses. These transient modifications last for ~3 min, with a time course similar to post-tetanic potentiation at chemical synapses. However, a different stimulus pattern that transiently increases the presynaptic calcium concentration, paired-nerve stimuli, does not have any significant effect on electrotonic transmission, whereas it facilitates the chemically mediated EPSP. On the other hand, induction of the short-lasting potentiation of coupling, which depended on the discontinuous or burst-like property of the tetanizing paradigm, required NMDA-receptor activation and was blocked by postsynaptic intradendritic injections of the calcium chelator bis(2-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid. The ineffectiveness of presynaptic calcium in potentiating electrotonic coupling likely reflects the involvement of a calcium-dependent regulatory protein in the postsynaptic cell and suggests that hemichannels on the two aides of a gap junction plaque can be modified independently. NMDA-mediated modulation of gap junctions could be widespread, because both types of channels coexist during development and in several mammalian adult central nervous system structures such as hippocampus.
KW - Mauthner cell
KW - NMDA
KW - activity-dependent plasticity
KW - calcium
KW - electrical synapses
KW - gap junctions
KW - glutamate
UR - http://www.scopus.com/inward/record.url?scp=0030010441&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030010441&partnerID=8YFLogxK
U2 - 10.1523/jneurosci.16-03-00983.1996
DO - 10.1523/jneurosci.16-03-00983.1996
M3 - Article
C2 - 8558267
AN - SCOPUS:0030010441
VL - 16
SP - 983
EP - 992
JO - Journal of Neuroscience
JF - Journal of Neuroscience
SN - 0270-6474
IS - 3
ER -