Linked Life Data

10085360

Source:http://linkedlifedata.com/resource/pubmed/id/10085360

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1999-5-6
pubmed:abstractText
Apical dendrites of layer 5 pyramidal cells in a slice preparation of rat sensorimotor cortex were depolarized focally by long-lasting glutamate iontophoresis while recording intracellularly from their soma. In most cells the firing pattern evoked by the smallest dendritic depolarization that evoked spikes consisted of repetitive bursts of action potentials. During larger dendritic depolarizations initial burst firing was followed by regular spiking. As dendritic depolarization was increased further the duration (but not the firing rate) of the regular spiking increased, and the duration of burst firing decreased. Depolarization of the soma in most of the same cells evoked only regular spiking. When the dendrite was depolarized to a critical level below spike threshold, intrasomatic current pulses or excitatory postsynaptic potentials also triggered bursts instead of single spikes. The bursts were driven by a delayed depolarization (DD) that was triggered in an all-or-none manner along with the first Na+ spike of the burst. Somatic voltage-clamp experiments indicated that the action current underlying the DD was generated in the dendrite and was Ca2+ dependent. Thus the burst firing was caused by a Na+ spike-linked dendritic Ca2+ spike, a mechanism that was available only when the dendrite was adequately depolarized. Larger dendritic depolarization that evoked late, constant-frequency regular spiking also evoked a long-lasting, Ca2+-dependent action potential (a "plateau"). The duration of the plateau but not its amplitude was increased by stronger dendritic depolarization. Burst-generating dendritic Ca2+ spikes could not be elicited during this plateau. Thus plateau initiation was responsible for the termination of burst firing and the generation of the constant-frequency regular spiking. We conclude that somatic and dendritic depolarization can elicit quite different firing patterns in the same pyramidal neuron. The burst and regular spiking observed during dendritic depolarization are caused by two types of Ca2+-dependent dendritic action potentials. We discuss some functional implications of these observations.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0022-3077
pubmed:author
pubmed:issnType
Print
pubmed:volume
81
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1341-54
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Mechanisms underlying burst and regular spiking evoked by dendritic depolarization in layer 5 cortical pyramidal neurons.
pubmed:affiliation
Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, Washington 98195-7290, USA.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't