TY - JOUR
T1 - Long-lasting enhancement of metabotropic excitatory amino acid receptor-mediated polyphosphoinositide hydrolysis in the amygdala/ pyriform cortex of deep prepiriform cortical kindled rats
AU - Akiyama, Kazufumi
AU - Daigen, Akihiro
AU - Yamada, Norihito
AU - Itoh, Takashi
AU - Kohira, Ichiro
AU - Ujike, Hiroshi
AU - Otsuki, Saburo
N1 - Funding Information:
Acknowledgements. This study was supported by the Japanese Epilepsy Research Foundation and Grant fn Aid for Scientific Research 02770708, 1990, of the Ministry of Education, Science and Culture of Japan.
PY - 1992/1/8
Y1 - 1992/1/8
N2 - We have previously demonstrated that ibotenate (IBO)-stimulated polyphosphoinositide (PPI) hydrolysis is increased for a long period in the amygdala/pyriform cortex (AM/PC) of amygdala (AM)- and hippocampal (HIPP)-kindled rats1,2,37. This finding indicates that enhanced function of the PPI-coupled excitatory amino acid (EAA) receptor may be associated with the long-lasting seizure susceptibility of kindling. The present study further examined PPI hydrolysis induced by trans-ACPD, a selective agonist of the metabotropic EAA receptor, as well as by IBO in brain slices of rats kindled from the deep prepiriform cortex (DPC). IBO-stimulated accumulation of [3H]inositol monophosphate ([3H]InsP) was significantly increased in the AM/PC by 162 (P < 0.0001), 130 (P < 0.005) and 81% (P < 0.03) at 24 h, 7 days and 28 days, respectively, after the last kindled seizure, whereas it was increased significantly only at 24 h after the last seizure in the HIPP and did not change at any time in the limbic forebrain (LFB). The IBO-stimulated accumulation of [3H]InsP was significantly increased by 55% (P < 0.01) in the AM/PC of partially kindled rats reaching an average stage of 3.7, but not in the AM/PC of those remaining at stage 1,7 days after the last kindled seizure. Trans-ACPD-stimulated PPI hydrolysis was significantly increased in the AM/PC of DPC-kindled rats by 65 (P < 0.05) and 45% (P < 0.005) at 7 and 28 days, respectively, after the last kindled seizure. Cis-ACPD-stimulated PPI hydrolysis was also significantly increased in the AM/PC of DPC-kindled rats by 45 (P < 0.03) and 30% (P < 0.04) at 7 and 28 days, respectively, after the last seizure. There was no increase in trans-ACPD- or cis-ACPD-stimulated PPI hydrolysis in the HIPP or LFB. These results further confirm our previous studies showing that the metabotropic EAA receptor-stimulated PPI hydrolysis exhibited a long-lasting increase in the AM/PC irrespective of the primary stimulation site for kindling.
AB - We have previously demonstrated that ibotenate (IBO)-stimulated polyphosphoinositide (PPI) hydrolysis is increased for a long period in the amygdala/pyriform cortex (AM/PC) of amygdala (AM)- and hippocampal (HIPP)-kindled rats1,2,37. This finding indicates that enhanced function of the PPI-coupled excitatory amino acid (EAA) receptor may be associated with the long-lasting seizure susceptibility of kindling. The present study further examined PPI hydrolysis induced by trans-ACPD, a selective agonist of the metabotropic EAA receptor, as well as by IBO in brain slices of rats kindled from the deep prepiriform cortex (DPC). IBO-stimulated accumulation of [3H]inositol monophosphate ([3H]InsP) was significantly increased in the AM/PC by 162 (P < 0.0001), 130 (P < 0.005) and 81% (P < 0.03) at 24 h, 7 days and 28 days, respectively, after the last kindled seizure, whereas it was increased significantly only at 24 h after the last seizure in the HIPP and did not change at any time in the limbic forebrain (LFB). The IBO-stimulated accumulation of [3H]InsP was significantly increased by 55% (P < 0.01) in the AM/PC of partially kindled rats reaching an average stage of 3.7, but not in the AM/PC of those remaining at stage 1,7 days after the last kindled seizure. Trans-ACPD-stimulated PPI hydrolysis was significantly increased in the AM/PC of DPC-kindled rats by 65 (P < 0.05) and 45% (P < 0.005) at 7 and 28 days, respectively, after the last kindled seizure. Cis-ACPD-stimulated PPI hydrolysis was also significantly increased in the AM/PC of DPC-kindled rats by 45 (P < 0.03) and 30% (P < 0.04) at 7 and 28 days, respectively, after the last seizure. There was no increase in trans-ACPD- or cis-ACPD-stimulated PPI hydrolysis in the HIPP or LFB. These results further confirm our previous studies showing that the metabotropic EAA receptor-stimulated PPI hydrolysis exhibited a long-lasting increase in the AM/PC irrespective of the primary stimulation site for kindling.
KW - Amygdala
KW - Deep prepiriform cortex
KW - Epilepsy
KW - Ibotenate
KW - Kindling
KW - Metabotropic excitatory amino acid receptor
KW - Polyphosphoinositide hydrolysis
KW - trans-1-Amino-cyclopentyl-1,3-dicarboxylic acid
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UR - http://www.scopus.com/inward/citedby.url?scp=0026543001&partnerID=8YFLogxK
U2 - 10.1016/0006-8993(92)90370-O
DO - 10.1016/0006-8993(92)90370-O
M3 - Article
C2 - 1319260
AN - SCOPUS:0026543001
SN - 0006-8993
VL - 569
SP - 71
EP - 77
JO - Molecular Brain Research
JF - Molecular Brain Research
IS - 1
ER -