Glutamate modulates intracellular Ca2+ stores in brain stem auditory neurons.
1. Fura-2 imaging was used to measure the effects of glutamate on caffeine-sensitive Ca2+ stores in neurons of the avian cochlear nucleus, n. magnocellularis (NM). 2. On average, 100-mM caffeine stimulated a 250-nM increase in intracellular calcium ion concentration {[Ca2+]i} in Ca(2+)-free media; 1-mM glutamate significantly attenuated caffeine-stimulated Ca2+ responses. 3. The metabotropic glutamate receptor agonist, ACPD, also inhibited the caffeine-stimulated rise in [Ca2+]i. 4. Glutamate has an important role in regulating Ca2+ stores in NM neurons. Glutamate-deprivation (viz. cochlear removal) results in a rise in [Ca2+]i that may, in part, be the result of release from Ca2+ stores. We hypothesize that Ca(2+)-induced Ca2+ release stores (CICRs) may be involved in deprivation-induced cell death.
Kato
B M
BM
Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington School of Medicine, Seattle 98195, USA.
Lachica
E A
EA
Rubel
E W
EW
D000818:Animals; D001933:Brain Stem / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002642:Chick Embryo; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects*; D018698:Glutamic Acid / Q000494:pharmacology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism
D018698:Glutamic Acid; D002118:Calcium