Phasic and tonic modes of depolarization-exocytosis coupling in β-cells of porcine islets of Langerhans
| Autor: | Adam S. Dickey, Stanley Misler, David W. Barnett, Amélia M. Silva |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
Swine
Voltage clamp Biophysics Action Potentials chemistry.chemical_element Calcium Biology Biochemistry Exocytosis Membrane Potentials Tonic (physiology) Islets of Langerhans Insulin-Secreting Cells Animals Membrane potential Voltage-dependent calcium channel Depolarization Anatomy Electrophysiology Glucose chemistry Calcium Channels |
| Zdroj: | Channels. 3:101-109 |
| ISSN: | 1933-6969 1933-6950 |
| DOI: | 10.4161/chan.3.2.7866 |
| Popis: | In response to depolarizations that open voltage dependent Ca2+ channels single porcine beta-cells display heterogeneous time courses of exocytosis. Some cells display phasic exocytosis that is triggered by individual or short burst of action potentials typically characteristic of glucose-induced electrical activity or brief voltage clamp depolarization. Other cells, singularly or additionally, display tonic exocytosis that (i) is triggered during prolonged (up to seconds-long) depolarizations to voltages (-30 to -20 mV), and (ii) coincides with rises in global cytosolic [Ca2+] >500 nM. We suggest that tonic exocytosis (i) likely results from a recently described pool of granules that is more Ca2+ sensitive and less co-localized with voltage-sensitive Ca2+ entry channels than that contributing to phasic exocytosis and (ii) helps tune exocytosis to glucose-induced electrical activity when the latter consists of spike activity followed by intervals of plateau depolarization to nearly -20 mV. |
| Databáze: | OpenAIRE |
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