Synaptic connections of seizure-sensitive neurons in the dentate gyrus.
A selective loss of somatostatin- and neuropeptide Y-immunoreactive neurons has been reported in the dentate gyrus of rats with cerebral ischemia, following sustained electric stimulation, and in patients with non-tumor-related temporal lobe epilepsy. Three theoretical possibilities were tested that may explain why these neurons are more vulnerable than others, such as the cholecystokinin- and calcium-binding protein-containing cells: (1) the seizure-sensitive neurons are more involved in specific excitatory circuitry than are the seizure-resistant cells; (2) the somatostatin- and neuropeptide Y-immunoreactive neurons are less protected by inhibitory GABAergic inputs than cells immunoreactive for cholecystokinin; and (3) the seizure-sensitive neurons do not contain calcium-binding proteins. The present results of light and electron microscopic, single and double, immunostaining experiments and co-localization studies performed on the hippocampal formations of rats and non-human primates, support the idea that the calcium-binding protein content of a neuron defines its seizure sensitivity.
Leranth
C
C
Department of Obstetrics and Gynecology, School of Medicine, Yale University, New Haven, CT 06510.
Nitsch
R
R
Deller
T
T
Frotscher
M
M
D000818:Animals; D001931:Brain Mapping; D002135:Calcium-Binding Proteins / Q000502:physiology; D002522:Chlorocebus aethiops; D002766:Cholecystokinin / Q000502:physiology; D003594:Cytoplasmic Granules / Q000648:ultrastructure; D004833:Epilepsy, Temporal Lobe / Q000473:pathology / Q000503:physiopathology; D005260:Female; D006624:Hippocampus / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D008854:Microscopy, Electron; D009433:Neural Inhibition / Q000502:physiology; D009474:Neurons / Q000502:physiology; D009478:Neuropeptide Y / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012640:Seizures / Q000473:pathology / Q000503:physiopathology*; D013004:Somatostatin / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D002135:Calcium-Binding Proteins; D009478:Neuropeptide Y; D013004:Somatostatin; D005680:gamma-Aminobutyric Acid; D002766:Cholecystokinin