Long-Lasting Potentiation and Depression without Presynaptic Activity. Neveu, Dorine and Robert S. Zucker. Neurobiology Division, University of California, Berkeley, California 94720.
APStracts 3:0039N, 1996.
SUMMARY AND CONCLUSIONS
1. Long-term potentiation (LTP) and long-term depression (LTD) require a rise in intracellular Ca 2+ concentration ([Ca 2+ ] i ) in the post-synaptic CA1 pyramidal neuron to activate Ca-dependent biochemical processes. This rise in [Ca 2+ ] i is a necessary trigger for the induction of LTP and LTD, but it is unclear if concurrent presynaptic activity is required for their induction or expression. 2. We used photolysis of the caged-Ca 2+ compound nitr-5 to elevate postsynaptic [Ca 2+ ] i . Long-lasting potentiation (LLP) and long- lasting depression (LLD) were obtained in the absence of presynaptic activity. 3. As LLP and LLD share common features with LTP and LTD induced by presynaptic stimulation (Neveu and Zucker, 1996), these results show that a rise in [Ca 2+ ] i in the post-synaptic CA1 pyramidal neurons is necessary and sufficient for the induction and expression of LTP and LTD, and that concurrent presynaptic activity is not required.

Received 22 December 1995; accepted in final form 5 February 1996.
APS Manuscript Number J859-5.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 14 February 96