R-Type Ca<sup>2+</sup>Channels Are Coupled to the Rapid Component of Secretion in Mouse Adrenal Slice Chromaffin Cells

Journal of Neuroscience - Tập 20 Số 22 - Trang 8323-8330 - 2000
Almudena Albillos1,2, Erwin Neher1, Tobias Moser1,3
1Department of Membrane Biophysics, Max-Planck Institute for Biophysical Chemistry, 37077 Goettingen, Germany,
2Instituto de Farmacologı́a Teófilo Hernando, Departamento de Farmacologı́a y Terapeútica, Facultad de Medicina, Universidad Autónoma de Madrid, 28029 Madrid, Spain, and
3Department of Otolaryngology, Goettingen University Medical School, 37073 Goettingen, Germany

Tóm tắt

Patch-clamp measurements of Ca2+currents and membrane capacitance were performed on slices of mouse adrenal glands, using the perforated-patch configuration of the patch-clamp technique. These recording conditions are much closer to thein vivosituation than those used so far in most electrophysiological studies in adrenal chromaffin cells (isolated cells maintained in culture and whole-cell configuration). We observed profound discrepancies in the quantities of Ca2+channel subtypes (P-, Q-, N-, and L-type Ca2+channels) described for isolated mouse chromaffin cells maintained in culture. Differences with respect to previous studies may be attributable not only to culture conditions, but also to the patch-clamp configuration used. Our experiments revealed the presence of a Ca2+channel subtype never before described in chromaffin cells, a toxin and dihydropyridine-resistant Ca2+channel with fast inactivation kinetics, similar to the R-type Ca2+channel described in neurons. This channel contributes 22% to the total Ca2+current and controls 55% of the rapid secretory response evoked by short depolarizing pulses. Our results indicate that R-type Ca2+channels are in close proximity with the exocytotic machinery to rapidly regulate the secretory process.

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Journal of Neuroscience

Tập 20 Số 22

8323-8330

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