Linked Life Data

1979851

Source:http://linkedlifedata.com/resource/pubmed/id/1979851

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1991-2-1
pubmed:abstractText
Ion-selective microelectrodes can be used to evaluate the characteristics and laminar distribution of excitatory amino acid agonist-induced K+ and Ca2+ shifts in the extracellular environment of brain cells. This report describes the pattern of K+ increases and Ca2+ decreases elicited by glutamate and aspartate at 100 microns intervals in the isolated turtle cerebellum. These responses were compared to ion shifts evoked by kainate, quisqualate and N-methyl-D-aspartate. Glutamate and aspartate produced indistinguishable laminar patterns of ion shifts, with the greatest [K+]o and [Ca2+]o shifts in the granular layer. The average maximum granular and molecular layer increases in [K+]o were, respectively, 130% and 24% larger than the increase in the Purkinje cell layer. Kainate-induced increases in [K+]o also followed this granular greater than molecular greater than Purkinje cell layer pattern; however, the corresponding [Ca2+]o decreases were smaller and more variable. Quisqualate-evoked ion shifts in the molecular layer closely mimicked the shape of glutamate- and aspartate-induced responses. In the granular layer, however, quisqualate caused little ion change during iontophoresis followed by large [K+]o and [Ca+]o shifts after the end of the pulse. The minimal ion shifts induced during quisqualate application in the granular layer gave this agonist the distinction of being the only agent tested to have its greatest direct effect in the molecular layer. N-Methyl-D-aspartate caused large, two-phase [K+]o and [Ca2+]o shifts in the granular layer, only small [K+]o rises in the Purkinje cell and ventral molecular layers, and no response in the dorsal molecular layer. The lack of similarity between glutamate- and aspartate-induced ion shifts in the granular layer and those of any one agonist demonstrate the mixed agonist action of glutamate and aspartate in the cerebellum. These studies provide new information about the dynamics of excitatory amino acid receptor activation that is complementary to autoradiographic receptor mapping data and to single cell electrophysiological studies.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0306-4522
pubmed:author
pubmed:issnType
Print
pubmed:volume
38
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
295-310
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Glutamate- and aspartate-induced extracellular potassium and calcium shifts and their relation to those of kainate, quisqualate and N-methyl-D-aspartate in the isolated turtle cerebellum.
pubmed:affiliation
Department of Physiology and Biophysics, New York University Medical Center, NY 10016.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S.