Braha_1990_Proc.Natl.Acad.Sci.U.S.A_87_2040

Reference

Title : Second messengers involved in the two processes of presynaptic facilitation that contribute to sensitization and dishabituation in Aplysia sensory neurons - Braha_1990_Proc.Natl.Acad.Sci.U.S.A_87_2040
Author(s) : Braha O , Dale N , Hochner B , Klein M , Abrams TW , Kandel ER
Ref : Proc Natl Acad Sci U S A , 87 :2040 , 1990
Abstract :

Presynaptic facilitation of transmitter release contributes to behavioral sensitization and dishabituation, two simple forms of learning in Aplysia. This enhancement of transmitter release can be simulated by the facilitatory transmitter serotonin and has been shown to result from two types of mechanisms. The first facilitating process involves broadening of the presynaptic action potential in the sensory neurons of the reflex and is maximally effective when the synapse has not been depressed by repeated stimulation, as during sensitization. The second process is independent of changes in spike duration and can enhance release even when the synapse is quite depressed, as during dishabituation. Earlier work suggests that the first process is mediated by an increase in the intracellular level of cyclic AMP in the sensory neurons. We show here that release of free cyclic AMP from a photolyzable analogue introduced into sensory neurons can enhance release even at depressed synapses, indicating that cyclic AMP can activate the second as well as the first process. In addition, we find that phorbol esters, activators of protein kinase C, enhance release at depressed synapses. This is consistent with the report in the accompanying paper [Sacktor, T. C. and Schwartz, J. H. (1990) Proc. Natl. Acad. Sci. USA 87, 2036-2039] that serotonin and sensitizing stimuli translocate protein kinase C from cytoplasm to membrane. Our findings suggest that the cyclic AMP-dependent phosphorylation system can mediate more than one facilitatory process and that both cyclic AMP-dependent kinase and protein kinase C may be involved in facilitation of depressed synapses.

PubMedSearch : Braha_1990_Proc.Natl.Acad.Sci.U.S.A_87_2040
PubMedID: 2155432

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Citations formats

Braha O, Dale N, Hochner B, Klein M, Abrams TW, Kandel ER (1990)
Second messengers involved in the two processes of presynaptic facilitation that contribute to sensitization and dishabituation in Aplysia sensory neurons
Proc Natl Acad Sci U S A 87 :2040

Braha O, Dale N, Hochner B, Klein M, Abrams TW, Kandel ER (1990)
Proc Natl Acad Sci U S A 87 :2040