Autoradiographic analysis of second-messenger systems in the gerbil hippocampus following repeated brief ischemic insults.
Using [3H]inositol 1,4,5-triphosphate (IP3), [3H]phorbol 12,13-dibutyrate (PDBu) and [3H]forskolin, we performed quantitative autoradiography to determine sequential alterations in second-messenger systems in the gerbil hippocampus following repeated brief ischemic insults. Changes following three 2-min ischemic insults were compared with those following single 2- or 6-min ischemia. [3H]IP3 binding was extremely sensitive to ischemic insult, and more than 80% of the binding sites were lost after destruction of CA1 pyramidal cells following 6-min ischemia and three 2-min ischemic insults. Furthermore, a 30% reduction was observed after 2-min ischemia which leads to no neuronal loss. [3H]PDBu binding in the CA1 subfield decreased by 1 day after three 2-min ischemic insults and by 4 days after 6-min ischemia, and 40-50% reductions were observed at 1 month. In contrast, [3H]forskolin binding was relatively preserved. [3H]PDBu and [3H]forskolin binding transiently increased early in the reperfusion period. We also observed a difference in the pattern and severity of alterations between repeated ischemic insults and single ischemia.
Kato
H
H
Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.
Araki
T
T
Hara
H
H
Kogure
K
K
D000818:Animals; D001345:Autoradiography; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D005576:Colforsin / Q000378:metabolism; D005849:Gerbillinae; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008297:Male; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism; D015290:Second Messenger Systems
D005576:Colforsin; D015240:Phorbol 12,13-Dibutyrate; D015544:Inositol 1,4,5-Trisphosphate