INVESTIGADORES
SZCZUPAK Lidia
artículos
Título:
Calcium spikes in a leech nonspiking neuron
Autor/es:
LORENA RELA; SUNG MIN YANG; LIDIA SZCZUPAK
Revista:
JOURNAL OF COMPARATIVE PHYSIOLOGY A-SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY
Editorial:
Springer Berlin
Referencias:
Lugar: Heidelberg; Año: 2008 vol. 195 p. 139 - 150
ISSN:
0340-7594
Resumen:
The NS neurons are nonspiking cells, present as
pairs in each midbody ganglion of the leech nervous system,
which display a very extensive arborization. They
were shown to regulate the coactivation of motoneurons.
Here we have investigated the electrophysiological properties
of these neurons under the hypothesis that transmission
along the extensive neurites requires the aid of voltagedependent
conductances. The results indicate that NS neurons
respond to electrical stimulation with a spike-like
event, which was not an all-or-none but rather a graded
phenomenon that depended on the intensity and duration of
the electrical stimulus. The spike-like response was activated
at a membrane potential of approximately ¡50 mV;
its amplitude was a logarithmic function of the extracellular
Ca2+ concentration and was unaVected by a broad range of
changes in the extracellular Na+ concentration; intracellular
application of tetraethylammonium (TEA) caused a large
increase in its amplitude and duration. These data indicate
that NS neurons bear voltage-dependent low-threshold Ca2+
and TEA-sensitive K+ conductances that could contribute
to shaping synaptic signals, or transmission along the
extensive neuritic tree.