Long-lasting enhancement of metabotropic excitatory amino acid receptor-mediated polyphosphoinositide hydrolysis in the amygdala/pyriform cortex of deep prepiriform cortical kindled rats.

Abstract

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 rats. 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 less than 0.0001), 130 (P less than 0.005) and 81% (P less than 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 less than 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 less than 0.05) and 45% (P less than 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 less than 0.03) and 30% (P less than 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.

• Authors: K Akiyama, A Daigen, N Yamada, T Itoh, I Kohira, H Ujike, S Otsuki
• Journal: Brain research (Brain Res) Vol. 569 Issue 1 Pg. 71-7 (Jan 08 1992) ISSN: 0006-8993 [Print] Netherlands
• PMID: 1319260 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Neurotoxins
• Phosphatidylinositol Phosphates
• Phosphatidylinositols
• Receptors, Neurotransmitter
• Cycloleucine
• 1-amino-1,3-dicarboxycyclopentane
• Ibotenic Acid

Topics

• Amygdala (drug effects, metabolism, physiology)
• Animals
• Cerebral Cortex (drug effects, metabolism, physiology)
• Cycloleucine (analogs & derivatives, pharmacology)
• Electric Stimulation
• Hydrolysis
• Ibotenic Acid (pharmacology)
• Isomerism
• Kindling, Neurologic
• Limbic System (drug effects, metabolism, physiology)
• Male
• Neurotoxins (pharmacology)
• Phosphatidylinositol Phosphates
• Phosphatidylinositols (metabolism)
• Prosencephalon (drug effects, metabolism, physiology)
• Rats
• Rats, Inbred Strains
• Receptors, Neurotransmitter (drug effects, physiology)
• Seizures (metabolism)