Linked Life Data

2709342

Source:http://linkedlifedata.com/resource/pubmed/id/2709342

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1989-6-1
pubmed:abstractText
1. The amplitude-coding pyramidal neurons of the first-order nucleus in weakly electric gymnotiform fish (Eigenmannia), the electrosensory lateral line lobe (ELL), exhibit 2 major physiological transformations of primary afferent input. Pyramidal cells rapidly adapt to a step change in amplitude, and they have a center/surround receptive-field organization. This study examined the physiological role of GABAergic inhibition on pyramidal cells. GABAergic synapses onto the somata of pyramidal cells primarily originate from granule-cell interneurons along with descending input. 2. Pyramidal cells fall into two physiologically distinct categories: E units, which are excited by a rise in stimulus amplitude, and I units, which are inhibited by a rise in stimulus amplitude. Microiontophoretic application of bicuculline methiodide onto both types of pyramidal cells increased the time constant of adaptation, defined as the time required for the neuron's response to decay to 37% of its maximum value, by 70-90%. The peak firing rate of E units to a step increase in stimulus amplitude increased by 49%, while the firing rate of I units did not change significantly. 3. Bicuculline application demonstrated that GABAergic inhibition may contribute to the strict segregation of E and I response properties. In the presence of bicuculline, many E units (normally excited only by stimulus amplitude increases) became excited by both increases and decreases; many I units (normally excited only by amplitude decreases) also became excited to increases. 4. The size of the excitatory receptive-field of E units was not affected by bicuculline, although response magnitude increased. The inhibitory surround increased in spatial extent by 175% with bicuculline administration. Neither the size of the I unit receptive-field center nor the response magnitude changed in the presence of bicuculline. The antagonistic surround of I units, however, increased by 49%. 5. The anatomy of the ELL is well understood (see Carr and Maler 1986). The physiological results obtained in this study, along with the results of Bastian (1986a, b), further our understanding of the functional role of the ELL circuitry. Our results suggest that spatial and temporal response properties of pyramidal cells are regulated by different but interacting inhibitory interneurons, some of which use GABA as a neurotransmitter. The activity of these interneurons is in turn controlled by descending feedback systems.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0340-7594
pubmed:author
pubmed:issnType
Print
pubmed:volume
164
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
391-407
pubmed:dateRevised
2009-6-4
pubmed:meshHeading
pubmed:year
1989
pubmed:articleTitle
GABAergic inhibition shapes temporal and spatial response properties of pyramidal cells in the electrosensory lateral line lobe of gymnotiform fish.
pubmed:affiliation
Scripps Institution of Oceanography, University of California, San Diego, La Jolla 92093.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't