Innexins in the lobster stomatogastric nervous system: Cloning, phylogenetic analysis, developmental changes and expression within adult identified dye and electrically coupled neurons

E. Ducret, H. Alexopoulos, Y. Le Feuvre, J. A. Davies, P. Meyrand, J. P. Bacon, V. S. Fénelon
European Journal of Neuroscience. 2006-12-01; 24(11): 3119-3133
DOI: 10.1111/j.1460-9568.2006.05209.x

PubMed
Read on PubMed



Ducret E(1), Alexopoulos H, Le Feuvre Y, Davies JA, Meyrand P, Bacon JP, Fénelon VS.

Author information:
(1)Laboratoire de Neurobiologie des Réseaux, Université Bordeaux I & Centre
National de la Recherche Scientifique – Unité Mixte de Recherche 5816, Avenue des
Facultés, Talence 33405, France.

Gap junctions play a key role in the operation of neuronal networks by enabling
direct electrical and metabolic communication between neurons. Suitable models to
investigate their role in network operation and plasticity are invertebrate motor
networks, which are built of comparatively few identified neurons, and can be
examined throughout development; an excellent example is the lobster
stomatogastric nervous system. In invertebrates, gap junctions are formed by
proteins that belong to the innexin family. Here, we report the first molecular
characterization of two crustacean innexins: the lobster Homarus gammarus innexin
1 (Hg-inx1) and 2 (Hg-inx2). Phylogenetic analysis reveals that innexin gene
duplication occurred within the arthropod clade before the separation of insect
and crustacean lineages. Using in situ hybridization, we find that each innexin
is expressed within the adult and developing lobster stomatogastric nervous
system and undergoes a marked down-regulation throughout development within the
stomatogastric ganglion (STG). The number of innexin expressing neurons is
significantly higher in the embryo than in the adult. By combining in situ
hybridization, dye and electrical coupling experiments on identified neurons, we
demonstrate that adult neurons that express at least one innexin are dye and
electrically coupled with at least one other STG neuron. Finally, two STG neurons
display no detectable amount of either innexin mRNAs but may express weak
electrical coupling with other STG neurons, suggesting the existence of other
forms of innexins. Altogether, we provide evidence that innexins are expressed
within small neuronal networks built of dye and electrically coupled neurons and
may be developmentally regulated.

DOI: 10.1111/j.1460-9568.2006.05209.x
PMID: 17156373 [Indexed for MEDLINE]

Know more about