Journal of Comparative Physiology A

, Volume 155, Issue 3, pp 313–318 | Cite as

The cardio-regulator nerves of hermit crabs: Multimodal activation of the heart by the accelerator axons

  • Tohru Yazawa
  • Kiyoaki Kuwasawa


  1. 1.

    Some branches of the cardio-accelerator axons run directly to peripheral ganglionic tissue in the hermit crabs (Aniculus aniculus andDardanus crassimanus). Effects of the branches on cardiac tissues were studied electrophysiologically in a preparation in which the main trunk had been severed.

  2. 2.

    The branches of the cardio-accelerator axons exerted their acceleratory effects directly on two different tissues, peripheral motor processes of the ganglion and the myocardium.

  3. 3.

    Stimuli applied to the cardio-accelerator axons elicited impulses in ganglionic motor axons at terminal processes, but not in a one-to-one manner. For each ganglionic axon impulse an EJP was recorded from the myocardium. Therefore, the EJPs were identified as intrinsic EJPs due to activation of ganglionic axons by cardio-accelerator axons.

  4. 4.

    Small depolarizing potentials recorded from the myocardium corresponded one-to-one to stimuli applied to the cardio-accelerator axons. The following results show that the small potentials were EJPs: (i) The potentials showed summation and facilitation. (ii) Amplitude of the potentials varied depending on the level of the membrane potential. (iii) Amplitude of the potentials increased in a high Ca2+, low Mg2+ saline and decreased in a Ca2+-free, high Mg2+ saline. The EJPs were identified as extrinsic EJPs evoked directly in a muscle cell innervated by the accelerator axons.

  5. 5.

    The cardio-accelerator nerves excite the heart by multimodal activation, i.e. directly on the main trunk of the cardiac ganglion, on peripheral motor processes of the ganglion, and on the myocardium.



Muscle Cell Membrane Potential Cardiac Tissue Motor Process Hermit Crab 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



dorsal cardiac nerve


extrinsic EJP


intrinsic EJP


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Copyright information

© Springer-Verlag 1984

Authors and Affiliations

  • Tohru Yazawa
    • 1
  • Kiyoaki Kuwasawa
    • 1
  1. 1.Department of BiologyTokyo Metropolitan UniversityTokyoJapan

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