Linked Life Data

7601345

Source:http://linkedlifedata.com/resource/pubmed/id/7601345

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1995-8-10
pubmed:abstractText
Hormone secretion by GH3 pituitary cells is regulated by oscillations of the cytosolic Ca2+ concentration ([Ca2+]i), which are driven by electrical activity and modulated by hypothalamic releasing factors. We find that micromolar concentrations of L-glutamate and other acidic amino acids, but not selective excitatory amino acid receptor agonists, increase [Ca2+]i in GH3 cells. Activation by glutamate is blocked by dihydropyridines or removal of extracellular Ca2+ or Na+, but not by tetrodotoxin or excitatory amino acid receptor antagonists. Glutamate also accelerated the entry of Mn2+ used as a Ca2+ surrogate for Ca2+ channels. L-Glutamate and other acidic amino acids were taken up into GH3 cells by an Na(+)-dependent high-affinity transporter. The half-maximal effect of glutamate on [Ca2+]i was reached at concentrations similar to the Km for the glutamate transporter. Moreover, only those amino acids taken up through this transporter were able to increase [Ca2+]i. We propose that electrogenic entry of Na(+)-glutamate depolarizes the plasma membrane, thus causing an increase of action potentials firing and Ca2+ entry through voltage-gated channels. Our results suggest that glutamate may cooperate to the modulation of pituitary hormone secretion by an unconventional mechanism involving a high-affinity glutamate transporter rather than excitatory amino acid receptors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0892-6638
pubmed:author
pubmed:issnType
Print
pubmed:volume
9
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
815-9
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Glutamate increases cytosolic calcium in GH3 pituitary cells acting via a high-affinity glutamate transporter.
pubmed:affiliation
Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Universidad de Valladolid, Spain.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't