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This Article Full Text Full Text (PDF) All Versions of this Article: 573/3/711    most recent jphysiol.2006.109447v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Panatier, A. Articles by Oliet, S. H. R. Search for Related Content PubMed PubMed Citation Articles by Panatier, A. Articles by Oliet, S. H. R. Related Collections Neuroscience

¹ INSERM U.378, 33077 Bordeaux, France; Université Victor Segalen Bordeaux 2, 33077 Bordeaux France
² Centre for Research in Neuroscience, Montreal General Hospital and McGill University, Montreal H3G 1A4, Canada

Activity-dependent long-term synaptic changes were investigated at glutamatergic synapses in the supraoptic nucleus (SON) of the rat hypothalamus. In acute hypothalamic slices, high frequency stimulation (HFS) of afferent fibres caused long-term potentiation (LTP) of the amplitude of AMPA receptor-mediated excitatory postsynaptic currents (EPSCs) recorded with the whole-cell patch-clamp technique. LTP was also obtained in response to membrane depolarization paired with mild afferent stimulation. On the other hand, stimulating the inputs at 5 Hz for 3 min at resting membrane potential caused long-term depression (LTD) of excitatory transmission in the SON. These forms of synaptic plasticity required the activation of NMDA receptors since they were abolished in the presence of D-AP5 or ifenprodil, two selective blockers of these receptors. Analysis of paired-pulse facilitation and trial-to-trial variability indicated that LTP and LTD were not associated with changes in the probability of transmitter release, thereby suggesting that the locus of expression of these phenomena was postsynaptic. Using sharp microelectrode recordings in a hypothalamic explant preparation, we found that HFS also generates LTP at functionally defined glutamatergic synapses formed between the organum vasculosum lamina terminalis and SON neurons. Taken together, our findings indicate that glutamatergic synapses in the SON exhibit activity-dependent long-term synaptic changes similar to those prevailing in other brain areas. Such forms of plasticity could play an important role in the context of physiological responses, like dehydration or lactation, where the activity of presynaptic glutamatergic neurons is strongly increased.

(Received 11 March 2006; accepted after revision 11 April 2006; first published online 13 April 2006)
Corresponding author S. H. R. Oliet: INSERM U378 – Institut François Magendie, 146, rue Léo Saignat, 33077 Bordeaux Cedex, France. Email: stephane.oliet{at}bordeaux.inserm.fr

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