Abstract
We studied the modulation of the intracellular free calcium concentrations ([Ca 2+] i) by kainateJAMPA receptor activation in synaptosomes isolated from whole rat hippocampus, or from its CA1, CA3 or dentate gyrus subregions. The receptor was activated either by 100 μM S-α-amino-3-hydroxy-5-methyl-4-isoxazolopropionic acid (AMPA) (EC 50= 26.6 ± 4.9 μM) or by 100 μM kainate (EC 50 = 0.81 ± 0.1 μM), but the effects of these agonists were not additive. The response to either AMPA or kainate was competitively inhibited by 10 μM 6-cyano-7-nitroquinoxaline-2,3-dioxine. Higher [Ca 2+] i responses to 100 μM AMPA or to 100 μM kainate were observed in the CA3 subregion (43.2 ± 2.5 nM or 42.8 ± 2.3 nM, respectively) than in the whole hippocampus (22.4 ± 1.1 nM or 22.4 ± 1.6, respectively), in the CA1 subregion (26.4 ± 1.1 nM or 26.6 ± 2.6 nM, respectively) or in dentate gyrus (24.6 ± 1.4 nM or 21.5 ± 1.0 nM, respectively). These results indicate that the CA3 subregion of the hippocampus is enriched in a presynaptic high-affinity kainate receptor which modulates the [Ca 2+] i in nerve terminals.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
