Enhanced neurogenesis and possible synaptic reorganization in the piriform cortex of adult rat following kainic acid‐induced status epilepticus

Abstract

Epileptic seizure has been reported to enhance adult neurogenesis and induce aberrant synaptic reorganization in the human dentate gyrus in the hippocampal formation. However, adult neurogenesis in the extrahippocampal regions has not been well studied. To investigate seizure-enhanced neurogenesis in the extrahippocampal regions, we performed histological and immunohistochemical as well as western blot analyses on the cerebrum of Sprague-Dawley rats (n = 51, male, 7 weeks old, body weight 250-300 g) treated with intraperitoneal injection of kainic acid (KA, 10 mg/kg) to induce status epilepticus (SE) (n = 36) or normal saline solution (n = 15) followed by 5'-bromo-2-deoxyuridine (BrdU) injection to label newborn cells. Even though severe neuronal damage was found in the piriform cortex of rats having SE, immunohistochemistry for double cortin (DCX) revealed an increase in the number of immature neurons in the piriform cortex. Double immunofluorescence staining demonstrated that DCX-positive cells in the piriform cortex were positive for both BrdU and neuronal nuclear antigen. Immunohistochemistry and western blotting revealed increased expressions of synaptophysin and postsynaptic density protein 95 in the piriform cortex of rat having SE. These results suggested the enhanced neurogenesis and possible synaptic reorganization in the piriform cortex of the KA-treated rat.

Synergistic neuroprotective action of prolactin and 17β-estradiol on kainic acid-induced hippocampal injury and long-term memory deficit in ovariectomized rats

“…Furthermore, it has been reported that KA-induced epileptic seizures are followed by enhanced neurogenesis [43], while KA lesions in neonatal rats induce cell proliferation in CA1 and CA3 hippocampal sub elds [44].…”

Alzheimer’s Disease-like Pathological Features in the Dorsal Hippocampus of Wild-Type Rats Subjected to Methionine-Diet-Evoked Mild Hyperhomocysteinaemia

“…Impaired or disturbed hippocampal neurogenesis is part of the etiopathogenesis of neurodegenerative diseases, including AD. However, data are somewhat controversial in documenting increased or suppressed cell proliferation and show the vital roles of neuroinflammation and microglia activation [ 54 , 55 , 56 ].…”

“… The scheme of possible mechanisms of how the hHcy affects the DG cells [ 22 , 23 , 54 , 55 , 56 , 69 , 70 ], partially created with (accessed on 25 June 2023). Abbreviations: ↑ —increased concentration/ratio; —decreased concentration/ratio; IL—interleukin; NF-κb—nuclear factor-kappa beta; ROS—reactive oxygen species; TNF-α—tumour necrosis factor.…”

LRP4 is required for the olfactory association task in the piriform cortex

“…However, a subpopulation of immature neurons in layer II express DCX (doublecortin) and PSA-NCAM (polysialylated neural cell adhesion molecule) [ 30 , 36 – 38 ]. Therefore, the piriform cortex possesses slight adult neurogenesis [ 38 – 40 ]. So, PSA-NCAM positive neurons may also express GFAP, and the GFAP-positive cells in the piriform cortex may not be astrocytes [ 41 ].…”