PT  - JOURNAL ARTICLE
AU  - AE Pereda
AU  - DS Faber
TI  - Activity-dependent short-term enhancement of intercellular coupling
AID  - 10.1523/JNEUROSCI.16-03-00983.1996
DP  - 1996 Feb 01
TA  - The Journal of Neuroscience
PG  - 983--992
VI  - 16
IP  - 3
4099  - http://www.jneurosci.org/content/16/3/983.short
4100  - http://www.jneurosci.org/content/16/3/983.full
SO  - J. Neurosci.1996 Feb 01; 16
AB  - It was reported previously that repeated brief tetanization of the posterior eight 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 approximately 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 sides 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.