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Ca 2+ ‐Mediated Plateau Potentials in a Subpopulation of Interneurons in the Ventral Horn of the Turtle Spinal Cord
Author(s) -
Hounsgaard J.,
Kjaerulff O.
Publication year - 1992
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1992.tb00865.x
Subject(s) - spinal cord , neuroscience , depolarization , tetrodotoxin , anatomy , plateau (mathematics) , nucleus , electrophysiology , spike potential , biology , chemistry , biophysics , mathematical analysis , mathematics
The response properties of interneurons in the ventral horn were studied in transverse slices of segments D 8 to S 2 from the turtle spinal cord, using the current clamp technique. In about half of the neurons the response properties were dominated by their ability to generate plateau potentials. In these cells the plateau potential could account for delayed onset of spiking and a phase of increasing spike frequency during depolarizing current pulses and for a depolarizing afterpotential following the stimulus. The cells usually received monosynaptic and polysynaptic input from the ipsilateral dorsal root and occasionally from the contralateral root. The plateau potential was insensitive to tetrodotoxin but blocked by nifedipine and by replacing Ca 2+ with Co 2+ in the medium. It is concluded that the response properties of neurons in the ventral horn outside the motor nucleus have differentiated response properties that may well contribute to spinal motor function.