Malfunction of Respiratory-Related Neuronal Activity in Na + , K + -ATPase α2 Subunit-Deficient Mice Is Attributable to Abnormal Cl - Homeostasis in Brainstem Neurons

• Published in: The Journal of neuroscience Vol. 24; no. 47; pp. 10693 - 10701
• Main Authors: Ikeda, Keiko, Onimaru, Hiroshi, Yamada, Junko, Inoue, Koichi, Ueno, Shinya, Onaka, Tatsushi, Toyoda, Hiroki, Arata, Akiko, Ishikawa, Tomo-o, Taketo, Makoto M., Fukuda, Atsuo, Kawakami, Kiyoshi
• Format: Journal Article
• Language: English
• Published: Society for Neuroscience 24.11.2004
• Subjects: Behavioral/Systems/Cognitive
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/JNEUROSCI.2909-04.2004

Na + , K + -ATPase α2 subunit gene ( Atp1a2 ) knock-out homozygous mice ( Atp1a2 - / - ) died immediately after birth resulting from lack of breathing. The respiratory-related neuron activity in Atp1a2 - / - was investigated using a brainstem-spinal cord en bloc preparation. The respiratory motoneuron activity recorded from the fourth cervical ventral root (C4) was defective in Atp1a2 - / - fetuses of embryonic day 18.5. The C4 response to electrical stimulation of the ventrolateral medulla (VLM) recovered more slowly in Atp1a2 - / - than in wild type during superfusion with Krebs' solution, consistent with the high extracellular GABA in brain of Atp1a2 - / - . Lack of inhibitory neural activities in VLM of Atp1a2 - / - was observed by optical recordings. High intracellular Cl - concentrations in neurons of the VLM of Atp1a2 - / - were detected in gramicidin-perforated patch-clamp recordings. The α2 subunit and a neuron-specific K-Cl cotransporter KCC2 were coimmunoprecipitated in a purified synaptic membrane fraction of wild-type fetuses. Based on these results, we propose a model for functional coupling between the Na + , K + -ATPase α2 subunit and KCC2, which excludes Cl - from the cytosol in respiratory center neurons.