Activity-dependent synaptic plasticity in the supraoptic nucleus of the rat hypothalamus
The Journal of Physiology. 2006-06-07; 573(3): 711-721
DOI: 10.1113/jphysiol.2006.109447
Read on PubMed
1. J Physiol. 2006 Jun 15;573(Pt 3):711-21. Epub 2006 Apr 13.
Activity-dependent synaptic plasticity in the supraoptic nucleus of the rat
hypothalamus.
Panatier A(1), Gentles SJ, Bourque CW, Oliet SH.
Author information:
(1)INSERM U378, 33077 Bordeaux, France.
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.
DOI: 10.1113/jphysiol.2006.109447
PMCID: PMC1779752
PMID: 16613872 [Indexed for MEDLINE]