Differences between rats and rabbits in NMDA receptor-mediated calcium signalling in hippocampal neurones.
In vivo microdialysis combined with the measurement of (45)Ca(2+) efflux from prelabelled hippocampus demonstrated a pronounced N-methyl-D-aspartate (NMDA)-evoked (45)Ca(2+) release to the dialysate in the rat dentate gyrus (DG) and CA1, whereas in rabbit a slight release of (45)Ca(2+) was observed only in the DG. In vitro, we noticed that the NMDA-evoked increase in Fura-2 detected intracellular Ca(2+) concentration in synaptoneurosomes from the rat, but not from the rabbit hippocampus, was strongly inhibited by the ryanodine receptor (RyR) antagonists dantrolene and ryanodine. To establish the mechanism of these differences, we characterised their possible dependence on the expression of RyR and their co-localisation with the calcium binding protein calbindin D(28k). A pronounced expression of [(3)H]ryanodine binding sites in the rat DG, which is only slight in the CA1, was demonstrated whereas in rabbit they were only found in the DG. The pattern of expression of calbindin D(28k) immunoreactivity and RyR in the rat and rabbit hippocampus was similar. These results suggest that the functional role of RyR in the generation of the NMDA receptor-mediated intracellular Ca(2+) signalling in the rabbit hippocampal neurones is marginal when compared to the rat. These differences reflect a diverse expression of RyR in both species. The corresponding differences in calbindin D(28k) immunoreactivity are most probably secondary in nature.
Salinska
E
E
Department of Neurochemistry, Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.
Ziembowicz
A
A
Gordon-Krajcer
W
W
Skangiel-Kramska
J
J
Jablonska
B
B
Makarewicz
D
D
Zieminska
E
E
Lazarewicz
J W
JW
D000818:Animals; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology; D064026:Calbindins; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005260:Female; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D016202:N-Methylaspartate / Q000494:pharmacology; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011817:Rabbits / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats / Q000378:metabolism*; D017208:Rats, Wistar / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000378:metabolism*; D012433:Ryanodine / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects / Q000378:metabolism; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism; D014316:Tritium
D064026:Calbindins; D018690:Excitatory Amino Acid Agonists; D016194:Receptors, N-Methyl-D-Aspartate; D019837:Ryanodine Receptor Calcium Release Channel; D064030:S100 Calcium Binding Protein G; D014316:Tritium; D012433:Ryanodine; D016202:N-Methylaspartate; D002118:Calcium