Functional effect of somatostatin receptor 1 activation on synaptic transmission in the mouse hyppocampus
Author(s)
Cammalleri, Maurizio
Martini, Davide
Timperio, Anna Maria
Bagnoli, Paola
Date Issued
2009
Type
Article
Abstract
Somatostatin-14 (SRIF) co-localizes with GABA in the hippocampus
and regulates neuronal excitability. A role of SRIF
in the control of hippocampal activity has been proposed,
although the exact contribution of each SRIF receptor (sst1–
sst5) in mediating SRIF action requires some clarification. We
used hippocampal slices of wild-type and sst1 knockout (KO)
mice and selective pharmacological tools to provide conclusive
evidence for a role of sst1 in mediating SRIF inhibition of
synaptic transmission. With single- and double-label immunohistochemistry,
we determined the distribution of sst1 in
hippocampal slices and we quantified sst1 colocalization with
SRIF. With electrophysiology, we found that sst1 activation
with CH-275 inhibited both the NMDA- and the a-amino-
3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-mediated
responses. Results from sst1 KO slices confirmed the
specificity of CH-275 effects; sst1 activation did not affect the
inhibitory transmission which was in contrast increased by sst4
activation with L-803,087 in both wild-type and sst1 KO
slices. The AMPA-mediated responses were increased by
L-803,087. Functional interaction between sst1 and sst4 is
suggested by the finding that their combined activation prevented
the CH-275-induced inhibition of AMPA transmission.
The involvement of pre-synaptic mechanisms in mediating
inhibitory effects of sst1 on excitatory transmission was
demonstrated by the finding that CH-275 (i) increased the
paired-pulse facilitation ratio, (ii) did not influence the AMPA
depolarization in the presence of tetrodotoxin, and (iii) inhibited
glutamate release induced by epileptiform treatment. We
conclude that SRIF control of excitatory transmission through
an action at sst1 may represent an important contribution to
the regulation of hippocampal activity.
Additional information
L'articolo è disponibile sul sito dell'editore http://onlinelibrary.wiley.com/
Citation
Cammalleri, M. et al. 2009. Functional effect of somatostatin receptor 1 activation on synaptic transmission in the mouse hyppocampus. "Journal of Neurochemistry" 111(6): 1466-1477
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