Seizures increase trkC mRNA expression in the dentate gyrus of rat hippocampus. Role of glutamate receptor activation.
In this study we have shown, by in situ hybridization and RNase protection assay, a significant trkC mRNA increase confined to the dentate gyrus of hippocampus, both after seizures induced by intracerebroventricular injection of kainic acid and bicuculline. Moreover, after bicuculline treatment we observed an earlier increase of trkC mRNA level, which peaked after 3 h and returned back to normal levels by 12 h. In contrast, the kainic acid treatment produced a delayed increase of trkC mRNA, which initiated after 6 h, peaked at 12 h, and returned to normal levels at 24 h. This increase, which involves also trkC mRNA receptor with tyrosine kinase activity, was mediated by non-NMDA receptors and counteracted by GABA potentiating agent diazepam. Using embryonic neuronal cultures from cerebral hemispheres, including hippocampus, we found that glutamate receptor agonists, including glutamate, kainate, NMDA, and t-ACPD, increase trkC mRNA levels with the following rank order of efficacy: NMDA > t-ACPD > kainic acid > glutamate. In conclusion, our data show that trkC mRNA expression in granule cells of the hippocampus dentate gyrus is increased during seizure activity and that it is mediated by non-NMDA receptors.
Mudò
G
G
Institute of Human Physiology, Medical School, University of Catania, Italy.
Salin
T
T
Condorelli
D F
DF
Jiang
X H
XH
Dell'Albani
P
P
Timmusk
T
T
Metsis
M
M
Funakoshi
H
H
Belluardo
N
N
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D001640:Bicuculline / Q000494:pharmacology; D002478:Cells, Cultured / Q000502:physiology; D018891:Dentate Gyrus / Q000166:cytology / Q000503:physiopathology*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005333:Fetus / Q000502:physiology; D058787:GABA-A Receptor Antagonists; D015870:Gene Expression / Q000502:physiology; D017403:In Situ Hybridization; D007276:Injections, Intraventricular; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000502:physiology; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D020812:Receptor, trkC; D017475:Receptors, Nerve Growth Factor / Q000235:genetics*; D012260:Ribonucleases; D012640:Seizures / Q000139:chemically induced* / Q000503:physiopathology
D018690:Excitatory Amino Acid Agonists; D058787:GABA-A Receptor Antagonists; D012333:RNA, Messenger; D017475:Receptors, Nerve Growth Factor; D020794:Receptor Protein-Tyrosine Kinases; D020812:Receptor, trkC; D012260:Ribonucleases; D007608:Kainic Acid; D001640:Bicuculline