Congo red modulates ACh-induced Ca2+ oscillations in single pancreatic acinar cells of mice
Abstract
Ze-bing HUANG1, 2, 4, Hai-yan WANG3, Na-na SUN3, Jing-ke WANG3, Meng-qin ZHAO3, Jian-xin Shen3, Ming GAO2, Ronald P HAMMER Jr4, Xue-gong FAN1, *, Jie WU1, 2, 3, 4, *
1Department of Infectious Diseases, Xiangya Hospital, Central South University, and Key Laboratory of Viral Hepatitis, Changsha 410008, China; 2Divisions of Neurology and Neurobiology, Barrow Neurological Institute, St Joseph’s Hospital and Medical Center, Phoenix, AZ 8501, USA; 3Department of Physiology, Shantou University of Medical College, Shantou 210854, China; 4Departments of Basic Medical Sciences, Pharmacology and Psychiatry, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
Aim: Congo red, a secondary diazo dye, is usually used as an indicator for the presence of amyloid fibrils. Recent studies show that congo red exerts neuroprotective effects in a variety of models of neurodegenerative diseases. However, its pharmacological profile remains unknown. In this study, we investigated the effects of congo red on ACh-induced Ca2+ oscillations in mouse pancreatic acinar cells in vitro.
Methods: Acutely dissociated pancreatic acinar cells of mice were prepared. A U-tube drug application system was used to deliver drugs into the bath. Intracellular Ca2+ oscillations were monitored by whole-cell recording of Ca2+-activated Cl– currents and by using confocal Ca2+ imaging. For intracellular drug application, the drug was added in pipette solution and diffused into cell after the whole-cell configuration was established.
Results: Bath application of ACh (10 nmol/L) induced typical Ca2+ oscillations in dissociated pancreatic acinar cells. Addition of congo red (1, 10, 100 µmol/L) dose-dependently enhanced Ach-induced Ca2+ oscillations, but congo red alone did not induce any detectable response. Furthermore, this enhancement depended on the concentrations of ACh: congo red markedly enhanced the Ca2+ oscillations induced by ACh (10–30 nmol/L), but did not alter the Ca2+ oscillations induced by ACh (100–10000 nmol/L). Congo red also enhanced the Ca2+ oscillations induced by bath application of IP3 (30 µmol/L). Intracellular application of congo red failed to alter ACh-induced Ca2+ oscillations.
Conclusion: Congo red significantly modulates intracellular Ca2+ signaling in pancreatic acinar cells, and this pharmacological effect should be fully considered when developing congo red as a novel therapeutic drug.
Keywords: Congo red; pancreatic acinar cell; ACh; IP3; Ca2+ oscillation; whole-cell recording; Ca2+ image
Part of this work was supported by Shantou University Seed Fund (Jie WU) and by Guangdong Science and Technology Foundation (Hai-yan WANG).
* To whom correspondence should be addressed.
E-mail jie.wu@dignityhealth.org
Received 2014-05-03 Accepted 2014-08-19
Keywords:
1Department of Infectious Diseases, Xiangya Hospital, Central South University, and Key Laboratory of Viral Hepatitis, Changsha 410008, China; 2Divisions of Neurology and Neurobiology, Barrow Neurological Institute, St Joseph’s Hospital and Medical Center, Phoenix, AZ 8501, USA; 3Department of Physiology, Shantou University of Medical College, Shantou 210854, China; 4Departments of Basic Medical Sciences, Pharmacology and Psychiatry, University of Arizona College of Medicine, Phoenix, AZ 85004, USA
Aim: Congo red, a secondary diazo dye, is usually used as an indicator for the presence of amyloid fibrils. Recent studies show that congo red exerts neuroprotective effects in a variety of models of neurodegenerative diseases. However, its pharmacological profile remains unknown. In this study, we investigated the effects of congo red on ACh-induced Ca2+ oscillations in mouse pancreatic acinar cells in vitro.
Methods: Acutely dissociated pancreatic acinar cells of mice were prepared. A U-tube drug application system was used to deliver drugs into the bath. Intracellular Ca2+ oscillations were monitored by whole-cell recording of Ca2+-activated Cl– currents and by using confocal Ca2+ imaging. For intracellular drug application, the drug was added in pipette solution and diffused into cell after the whole-cell configuration was established.
Results: Bath application of ACh (10 nmol/L) induced typical Ca2+ oscillations in dissociated pancreatic acinar cells. Addition of congo red (1, 10, 100 µmol/L) dose-dependently enhanced Ach-induced Ca2+ oscillations, but congo red alone did not induce any detectable response. Furthermore, this enhancement depended on the concentrations of ACh: congo red markedly enhanced the Ca2+ oscillations induced by ACh (10–30 nmol/L), but did not alter the Ca2+ oscillations induced by ACh (100–10000 nmol/L). Congo red also enhanced the Ca2+ oscillations induced by bath application of IP3 (30 µmol/L). Intracellular application of congo red failed to alter ACh-induced Ca2+ oscillations.
Conclusion: Congo red significantly modulates intracellular Ca2+ signaling in pancreatic acinar cells, and this pharmacological effect should be fully considered when developing congo red as a novel therapeutic drug.
Keywords: Congo red; pancreatic acinar cell; ACh; IP3; Ca2+ oscillation; whole-cell recording; Ca2+ image
Part of this work was supported by Shantou University Seed Fund (Jie WU) and by Guangdong Science and Technology Foundation (Hai-yan WANG).
* To whom correspondence should be addressed.
E-mail jie.wu@dignityhealth.org
Received 2014-05-03 Accepted 2014-08-19