Expression of HCNl subunits is age-dependently regulated in developing hippocampus of rats |
Yoon-Sil Yang, Moon-Seok Kang, Seon-Hee Kim, Su-Yong Eun, Sung-Cherl Jung |
Department of Physiology, School of Medicine, Jeju National University, Jeju, Korea |
Correspondence:
Sung-Cherl Jung, Email: jungsc@jejunu.ac.kr |
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Abstract |
Hyperpolarization-activated, cyclic nucleotide-gated cation channels (HCN) encode hyperþolarization-activated cation current (Ih), playing regulatory roles in resting membrane properties, synaptic integration, and intrinsic exctabilities of hippocampal neurons. Expression patterns of HCN subtypes seem to be quietty variable to excitatory conditions of neurons, even though it has been previously observed that expression levels of HCN1, 2 and 4 are differentially regulated during developmental period. In the present study, we investigated expression patterns of HCN1 during an early developmental period within postnatal 3 weeks by using Western blot analysis. Inconsistent with previous reports, HCN1 expression was highest in neonatal and initial postnatal perlods, while neurons in postnatal third week revealed lower levels. This result indicates that HCN1 proteins are age dependently decreased during first postnatal 3 weeks. This finding suggests that CA1 neurons of early developmental hippocampi may have specific neuroprotective mechanisms correlated with HCN1 subunit against hyperexcitability or excitotoxic damages. |
Key Words:
Ih Channel; HCN1; hippocampus; excitotoxicity |
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