Altered distribution of KCC2 in cortical dysplasia in patients with intractable epilepsy

Mitsutoshi Munakata, Mika Watanabe, Taisuke Otsuki, Hideyuki Nakama, Kunimasa Arima, Masayuki Itoh, Junichi Nabekura, Kazuie Iinuma, Shigeru Tsuchiya

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)


Purpose: To examine the distribution of KCC2, a neuron-specific K +-Cl- cotransporter, in human cortical dysplasia (CD). Methods: The immunohistochemical expression of KCC2 was investigated in 18 CD specimens obtained during epilepsy surgery. The histopathologic diagnoses were focal CD (FCD) type I (eight cases), FCD type II (six cases), and hemimegalencephaly (HME; four cases). Tissue sections were immunostained for KCC2 and compared with control sections. Results: In the mature nondysplastic cortex, all the layers showed diffuse neuropil staining for KCC2. The somata were stained much less, although subcortical ectopic neurons displayed dense staining in the cytosol (intrasomatic staining). In FCD type I, the cortex showed neuropil staining for KCC2 with less-stained somata. Aberrant giant pyramidal neurons were also less stained at the soma, whereas immature neurons showed intrasomatic staining. Increased numbers of ectopic neurons with intrasomatic staining were noted in the subcortical white matter. In FCD type II, dysmorphic neurons displayed dense intrasomatic staining with reduced staining of the neighboring neuropils. Balloon cells did not stain for KCC2. Dysmorphic neurons in HME also showed intrasomatic staining. Conclusions: Neurons in CD tissues expressed KCC2. However, the subcellular distribution of KCC2 was altered, which might have affected the ionic homeostasis of Cl - and K+ involved in epileptic activity within CD tissues.

Original languageEnglish
Pages (from-to)837-844
Number of pages8
Issue number4
Publication statusPublished - 2007 Apr
Externally publishedYes


  • Focal cortical dysplasia
  • Hemimegalencephaly
  • Human
  • KCC2

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


Dive into the research topics of 'Altered distribution of KCC2 in cortical dysplasia in patients with intractable epilepsy'. Together they form a unique fingerprint.

Cite this