Abstracts

RATIONALE: Previously, we reported that the ventral hippocampal seizures were more intense than the dorsal hippocampal seizures. We also stated that hippocampal transection between dorsal hippocampus (dH) and ventral hippocampus (vH) attenuated KA-induced hippocampal seizures, especially in vH seizures. This study was designed to investigate metabolic aspects of hippocampal transection in KA-induced hippocampal seizures in rats, using [14C]2-deoxyglucose (DG) autoradiography.
METHODS: Twenty-six male Wistar rats were used for the local cerebral glucose utilization (LCGU) study. Stereotactic operation was performed under pentobarbital anesthesia. A stainless steel cannula was inserted into the left (L) dH (group 1, with transection animals; n=6, controls; n=6) or left (L) vH (group 2, with transection animals; n=8, controls; n=6). Under general anesthesia, they underwent insertion of catheters into the femoral vein. After recovery from the anethesia, all rats, given a KA (1.0 microgram) injection into the LdH or LvH, developed limbic status epilepticus. Ninety minutes after KA injection, DG (100 micro Ci/kg body weight) was administered via the femoral vein. Thirty min after DG administation, rats were decapitated and autoradiographic study was done.
RESULTS: (group 1) control rats; a moderate increases of LCGU were observrd in the LdH, LvH, amygdala and septal nucleus on the KA-injected side. Further, increases of LCGU in the sensorimotor cortex was slight.with transection rats; LCGU in the hippocampus, amygdala, and sensorimotor cortex were slightly decreased in comparison with the control rats.
(group 2) control rats; marked increases of LCGU were demonstrated in the bilateral dH and vH, amygdala, septal nucleus, mediodorsal nucleus, and sensorimotor cortex on the KA-injected side .
with transection rats; a mild increases of LCGU were observed in the vH on the KA-injected side, however, no significan increases of LCGU were demonstrated in the other structures. Especially in the ipsilateral dH, LCGU was decreased in comparison with the ipsilateral vH and contralateral dH.
CONCLUSIONS: In rats with hippocampal transection compared to those without transection, LCGU were decreased, especially in the hippocampus and amygdala which were considered as main structures to sustain limbic status epilepticus. These findings were compatible with our previous results in the electrophysiologic and behavioral study, and also suggested that the intrahippocampal correlation between the dorsal and ventral divisions may be critical for development and continuation of hippocampal seizures.
Support: Grant-in-Aid for Encouragement of Young Scientists from the Ministry of Education, Sciences, and Culture of Japan.
Disclosure: Grant - Grant-in-Aid for Encouragement of Young Scientists from the Ministry of Education, Sciences, and Culture of Japan.