CeN neuron

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CeN neuron is a Neuron in Melibe.

Basic information

Immunohistochemistry for nitric oxide synthase (NOS) shows a single, bilaterally symmetric NOS-immunoreactive neuron in the cerebral ganglion that projects to the ipsilateral pedal ganglion.
  • Names and Aliases - NOS Cell, N-cell.
  • Species: Melibe leonina
  • NeuronBank ID: Mel0002246
  • Neurotransmitter: Nitric oxide

There is one CeN neuron in each hemisphere of the cerebropleural ganglion. The axon projects ipsilaterally to the pedal ganglion. The CeN neuron can inhibit the swim motor pattern, possibly through a cGMP-dependent mechanism.

Identification

Anatomy:

  • NOS-immunoreactive neuron located in each cerebropleural ganglion and projecting to ipsilateral pedal ganglion.
  • Soma located on the lateral side of the juncture between the cerebral and pleural ganglia.
  • The axon projects ipsilaterally to the pedal ganglion. Along the way, there are fine branches projecting anteriorally into the cerebral ganglion. In the ipsilateral pedal ganglion, the axon bifurcates and surrounds the pedal neuropil in the center of the ganglion.
  • The axon is not known to project out of the ipsilateral pedal ganglion.

Electrophysiology and Pharmacology:

Simultaneous intracellular recordings from right CeN neuron and right swim motoneuron. Depolarization of the CeN neuron (between arrows) eventually inhibited bursting in the swim motoneuron. Bursting returned after cessation of the CeN depolarization. Vertical scale bar = 50 mV, horizontal scale bar = 5 s
  • During a swim motor pattern, the membrane potential, and occasional spikes, of the CeN neuron typically oscillates in phase with contralateral swim neurons.
  • Offset of light input causes temporary excitation of the CeN neuron.
  • Stimulation of a CeN neuron inhibits the swim motor pattern, although the stimulation must typically occur for >10 s for this inhibition to occur. The inhibition is temporary because the swim motor pattern resumes shortly (5-10 s) after the CeN neuron is no longer depolarized.
  • The nitric oxide scavenger hemoglobin can prevent this CeN-induced inhibition of the swim motor pattern. Bath application of the nitric oxide donors, such as sodium nitroprusside and S-nitroso-N-acetylpenicillamine, also inhibits the swim motor pattern. The CeN neurons are the only NOS-immunoreactive neurons in the brain, suggesting that the CeN neurons inhibit the swim motor pattern via nitric oxide.
  • The cGMP analogue 8-bromoguanosine 3':5'-cyclic monophosphate also inhibits the swim motor pattern, suggesting that nitric oxide may operate via a cGMP-mediated mechanism.

References

  1. Newcomb JM, Watson WH, III (2001) Identifiable nitrergic neurons in the central nervous system of the nudibranch Melibe leonina, localized with NADPH-diaphorase histochemistry and nitric oxide synthase immunoreactivity. J Comp Neurol 437: 70-78.
  2. Newcomb JM (2001) Nitric oxide in the central nervous system of the gastropod Melibe leonina and its role in modulation of swimming. Master's Thesis. University of New Hampshire, Durham, NH.
  3. Newcomb JM, Watson WH, III (2002) Modulation of swimming in the gastropod Melibe leonina by nitric oxide. J Exp Biol 205: 397-403.