Journal of Comparative Physiology A

, Volume 190, Issue 8, pp 615–622

Synaptic interactions between nonspiking local interneurones in the terminal abdominal ganglion of the crayfish

Original Paper

DOI: 10.1007/s00359-004-0516-5

Cite this article as:
Namba, H. & Nagayama, T. J Comp Physiol A (2004) 190: 615. doi:10.1007/s00359-004-0516-5


Nonspiking local interneurones are the important premotor elements in arthropod motor control systems. We have analyzed the synaptic interactions between nonspiking interneurones in the crayfish terminal (6th) abdominal ganglion using simultaneous intracellular recordings. Only 15% of nonspiking interneurones formed bi-directional excitatory connections. In 77% of connections, however, the nonspiking interneurones showed a one-way inhibitory interaction. In these cases, the presynaptic nonspiking interneurones received excitatory synaptic inputs from the sensory afferents innervating hairs on the surface of the uropods and the postsynaptic nonspiking interneurones received inhibitory synaptic inputs that were partly mediated by the inputs to the presynaptic nonspiking interneurones. The membrane hyperpolarization of the postsynaptic nonspiking interneurones mediated by the presynaptic nonspiking interneurones was reduced in amplitude when the hyperpolarizing current was injected into the postsynaptic interneurones, or when the external bathing solution was replaced with one containing low calcium and high magnesium concentrations. The role of these interactions in the circuits controlling the movements of the terminal appendages is discussed.


GABA Graded transmission Interneurone Local circuit Reflex 





excitatory postsynaptic potential


inhibitory postsynaptic potential



Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Animal Behaviour and Intelligence, Division of Biological Sciences, Graduate School of ScienceHokkaido UniversitySapporoJapan
  2. 2.Department of Molecular Neurobiology, Brain Research InstituteNiigata UniversityNiigataJapan

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