Altered expression of adrenocorticotropic hormone in the epileptic gerbil hippocampus following spontaneous seizure

Abstract

We investigated the temporal alterations of adrenocorticotropichormone (ACTH) immunoreactivity in the hippocampus afterseizure onset. Expression of ACTH was observed within interneuronsin the pre-seizure group of seizure sensitive gerbils,whereas its immunoreactivities were rarely detected in seizureresistant gerbil. Three hr after the seizure, ACTH immunoreactivitywas significantly increased in interneurons within allhippocampal regions. On the basis of their localization andmorphology through immunofluorescence staining, these cellswere identified as GABAA α1-containing interneurons. At the 12hr postictal period, ACTH expression in these regions wasdown-regulated, in a similar manner to the pre-seizure group ofgerbils. These findings support the increase in ACTH synthesisthat contributes to a reduction of corticotrophin-releasing factorvia the negative feedback system which in turn provides anopportunity to enhance the excitability of GABAergic interneurons.Therefore, ACTH may play an important role in thereduction of excitotoxicity in all hippocampal regions. [BMBReports 2013; 46(2): 80-85]

Keywords

• Adrenocorticotropic hormone
• Epilepsy
• Gerbil
• Hippocampus
• Immunohistochemistry