Hyo Young Jung1,2, Woosuk Kim3,4, Kyu Ri Hahn1, Min Soo Kang5, Hyun Jung Kwon3, Jung Hoon Choi5, Yeo Sung Yoon1, Dae Won Kim6, Dae Young Yoo7, Moo-Ho Won8, In Koo Hwang1. 1. Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University. 2. Seoul 08826, South Korea. 3. Department of Veterinary Medicine & Institute of Veterinary Science, Chungnam National University, Daejeon 34134, South Korea. 4. Department of Biomedical Sciences, and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 24252, South Korea. 5. Department of Anatomy, College of Veterinary Medicine, and Veterinary Science Research Institute, Konkuk University, Seoul 05030, South Korea. 6. Department of Anatomy, College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341. 7. South Korea. 8. Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University.
Abstract
Objectives: Vacuolar H+-ATPase is a highly conserved enzyme that plays an important role in maintaining an acidic environment for lysosomal function and accumulating neurotransmitters in synaptic vesicles. In the present study, we investigated the time-dependent changes in the expression of vacuolar H+-ATPase V1B2 (ATP6V1B2), a major neuronal subtype of vacuolar H+-ATPase located in the hippocampus, after 5 min of transient forebrain ischemia in gerbils. We also examined the pH and lactate levels in the hippocampus after ischemia to elucidate the correlation between ATP6V1B2 expression and acidosis. Materials and Methods: Transient forebrain ischemia was induced by occlusion of both common carotid arteries for 5 min and animals were sacrificed at various time points after ischemia for immunohistochemical staining of ATP6V1B2 and measurements of pH and lactate levels in the hippocampus. Results: ATP6V1B2 immunoreactivity was found to be transiently increased in the hippocampal CA1 region and dentate gyrus 12-24 hr after ischemia when the pH and lactate levels were decreased. In addition, ATP6V1B2 immunoreactivity significantly increased in the hippocampal CA3 and dentate gyrus, regions relatively resistant to ischemic damage, 4 days after ischemia, when the NeuN-positive, mature neuron numbers were significantly decreased in the hippocampal CA1 region. Conclusion: These results suggest that ATP6V1B2 expression is transiently increased in the hippocampus following ischemia, which may be intended to compensate for ischemia-related dysfunction of ATP6V1B2 in the hippocampus.
Objectives: Vacuolar H+-ATPase is a highly conserved enzyme that plays an important role in maintaining an acidic environment for lysosomal function and accumulating neurotransmitters in synaptic vesicles. In the present study, we investigated the time-dependent changes in the expression of vacuolar H+-ATPase V1B2 (ATP6V1B2), a major neuronal subtype of vacuolar H+-ATPase located in the hippocampus, after 5 min of transient forebrain ischemia in gerbils. We also examined the pH and lactate levels in the hippocampus after ischemia to elucidate the correlation between ATP6V1B2 expression and acidosis. Materials and Methods: Transient forebrain ischemia was induced by occlusion of both common carotid arteries for 5 min and animals were sacrificed at various time points after ischemia for immunohistochemical staining of ATP6V1B2 and measurements of pH and lactate levels in the hippocampus. Results: ATP6V1B2 immunoreactivity was found to be transiently increased in the hippocampal CA1 region and dentate gyrus 12-24 hr after ischemia when the pH and lactate levels were decreased. In addition, ATP6V1B2 immunoreactivity significantly increased in the hippocampal CA3 and dentate gyrus, regions relatively resistant to ischemic damage, 4 days after ischemia, when the NeuN-positive, mature neuron numbers were significantly decreased in the hippocampal CA1 region. Conclusion: These results suggest that ATP6V1B2 expression is transiently increased in the hippocampus following ischemia, which may be intended to compensate for ischemia-related dysfunction of ATP6V1B2 in the hippocampus.
Authors: Luca Vedovelli; John T Rothermel; Karin E Finberg; Carsten A Wagner; Anie Azroyan; Eric Hill; Sylvie Breton; Dennis Brown; Teodor G Paunescu Journal: Am J Physiol Renal Physiol Date: 2012-12-26