Pharmacological and biophysical properties of Ca2+ channels and subtype distributions in human adrenal chromaffin cells
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Pharmacological and biophysical properties of Ca2+ channels and subtype distributions in human adrenal chromaffin cells. / Pérez-Alvarez, Alberto; Hernández-Vivanco, Alicia; Cano-Abad, María; Albillos, Almudena.
In: PFLUG ARCH EUR J PHY, Vol. 456, No. 6, 09.2008, p. 1149-62.Research output: SCORING: Contribution to journal › SCORING: Journal article › Research › peer-review
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T1 - Pharmacological and biophysical properties of Ca2+ channels and subtype distributions in human adrenal chromaffin cells
AU - Pérez-Alvarez, Alberto
AU - Hernández-Vivanco, Alicia
AU - Cano-Abad, María
AU - Albillos, Almudena
PY - 2008/9
Y1 - 2008/9
N2 - In this study, we explored the pharmacological and biophysical properties of voltage-activated Ca2+ channels in human chromaffin cells using the perforated-patch configuration of the patch-clamp technique. According to their pharmacological sensitivity to Ca2+ channel blockers, cells could be sorted into two groups of similar size showing the predominance of either N- or P/Q-type Ca2+ channels. R-type Ca2+ channels, blocked by 77% with 20 muM Cd2+ and not affected by 50 muM Ni2+, were detected for the first time in human chromaffin cells. Immunocytochemical experiments revealed an even distribution of alpha (1E) Ca2+ channels in these cells. With regard to their biophysical properties, L- and R-type channels were activated at membrane potentials that were 15-20 mV more negative than P/Q- and N-type channels. Activation time constants showed no variation with voltage for the L-type channels, decreased with increasing potentials for the R- and P/Q-type channels, and displayed a bell shape with a maximum at 0 mV for the N-type channels. R-type channels were also the most inactivated channels. We thus show here that human chromaffin cells possess all the Ca2+ channel types described in neurons, L, N, P/Q, and R channels, but the relative contributions of N and P/Q channels differ among cells. Given that N- and P/Q-type Ca2+ channel types can be differentially modulated, these findings suggest the possibility of cell-specific regulation in human chromaffin cells.
AB - In this study, we explored the pharmacological and biophysical properties of voltage-activated Ca2+ channels in human chromaffin cells using the perforated-patch configuration of the patch-clamp technique. According to their pharmacological sensitivity to Ca2+ channel blockers, cells could be sorted into two groups of similar size showing the predominance of either N- or P/Q-type Ca2+ channels. R-type Ca2+ channels, blocked by 77% with 20 muM Cd2+ and not affected by 50 muM Ni2+, were detected for the first time in human chromaffin cells. Immunocytochemical experiments revealed an even distribution of alpha (1E) Ca2+ channels in these cells. With regard to their biophysical properties, L- and R-type channels were activated at membrane potentials that were 15-20 mV more negative than P/Q- and N-type channels. Activation time constants showed no variation with voltage for the L-type channels, decreased with increasing potentials for the R- and P/Q-type channels, and displayed a bell shape with a maximum at 0 mV for the N-type channels. R-type channels were also the most inactivated channels. We thus show here that human chromaffin cells possess all the Ca2+ channel types described in neurons, L, N, P/Q, and R channels, but the relative contributions of N and P/Q channels differ among cells. Given that N- and P/Q-type Ca2+ channel types can be differentially modulated, these findings suggest the possibility of cell-specific regulation in human chromaffin cells.
KW - Calcium Channel Blockers
KW - Calcium Channels
KW - Calcium Channels, R-Type
KW - Cation Transport Proteins
KW - Cells, Cultured
KW - Chromaffin Cells
KW - Dopamine beta-Hydroxylase
KW - Electrophysiology
KW - Humans
KW - Immunohistochemistry
KW - Patch-Clamp Techniques
KW - Phenylethanolamine N-Methyltransferase
KW - Journal Article
KW - Research Support, Non-U.S. Gov't
U2 - 10.1007/s00424-008-0492-7
DO - 10.1007/s00424-008-0492-7
M3 - SCORING: Journal article
C2 - 18443816
VL - 456
SP - 1149
EP - 1162
JO - PFLUG ARCH EUR J PHY
JF - PFLUG ARCH EUR J PHY
SN - 0031-6768
IS - 6
ER -