TY - JOUR
T1 - Ceramide modulates nicotinic receptor-dependent Ca2+ signaling in rat chromaffin cells
AU - Liu, Jihong
AU - Jorgensen, Mark S.
AU - Adams, Julye M.
AU - Titlow, William B.
AU - Nikolova-Karakashian, Mariana
AU - Jackson, Brian A.
PY - 2001/11/15
Y1 - 2001/11/15
N2 - Ceramide, which is an integral component of the sphingomyelin signaling pathway, can attenuate voltagegated Ca2+ channel (VGCC) activity in a number of cell types. The aim of the present study was to determine whether ceramide can also modulate VGCC activity, and as a consequence nicotinic receptor-dependent Ca2+ signaling and catecholamine secretion, in rat adrenal chromaffin cells. Short-term C6-ceramide (CER) treatment dose-dependently inhibited nicotine (NIC)-induced peak intracellular Ca2+ transients. Sphingomyelinase elicited similar responses, whereas the inactive ceramide analog C2-dihydroceramide had no effect on NICinduced Ca2+ transients. CER suppressed KCl- and NICinduced Ca2+ transients to a similar extent, suggesting that the voltage-gated Ca2+ channel was a primary site of inhibition. In direct support of this concept, whole-cell patch-clamp analysis demonstrated that CER and sphingomyelinase significantly reduced peak Ca2+ currents. Pretreatment with staurosporine significantly attenuated CER-dependent inhibition of both NIC-induced Ca2+ transients and peak Ca2+ current, suggesting that the effects of CER are mediated at least in part by protein kinase C. Consistent with suppressed Ca2+ signaling, CER also significantly inhibited NIC-induced catecholamine secretion measured at the single-cell level by carbon fiber amperometry. This effect of CER was also significantly attenuated by pretreatment with staurosporine These data demonstrate that the sphingomyelin signaling pathway can modulate nicotinic receptor-dependent Ca2+ signaling and catecholamine secretion in rat chromaffin cells.
AB - Ceramide, which is an integral component of the sphingomyelin signaling pathway, can attenuate voltagegated Ca2+ channel (VGCC) activity in a number of cell types. The aim of the present study was to determine whether ceramide can also modulate VGCC activity, and as a consequence nicotinic receptor-dependent Ca2+ signaling and catecholamine secretion, in rat adrenal chromaffin cells. Short-term C6-ceramide (CER) treatment dose-dependently inhibited nicotine (NIC)-induced peak intracellular Ca2+ transients. Sphingomyelinase elicited similar responses, whereas the inactive ceramide analog C2-dihydroceramide had no effect on NICinduced Ca2+ transients. CER suppressed KCl- and NICinduced Ca2+ transients to a similar extent, suggesting that the voltage-gated Ca2+ channel was a primary site of inhibition. In direct support of this concept, whole-cell patch-clamp analysis demonstrated that CER and sphingomyelinase significantly reduced peak Ca2+ currents. Pretreatment with staurosporine significantly attenuated CER-dependent inhibition of both NIC-induced Ca2+ transients and peak Ca2+ current, suggesting that the effects of CER are mediated at least in part by protein kinase C. Consistent with suppressed Ca2+ signaling, CER also significantly inhibited NIC-induced catecholamine secretion measured at the single-cell level by carbon fiber amperometry. This effect of CER was also significantly attenuated by pretreatment with staurosporine These data demonstrate that the sphingomyelin signaling pathway can modulate nicotinic receptor-dependent Ca2+ signaling and catecholamine secretion in rat chromaffin cells.
KW - Adrenal medulla
KW - Ca channels
KW - Catecholamines
KW - Ceramide
KW - Chromaffin cell
KW - Intracellular Ca
KW - Sphingomyelin
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U2 - 10.1002/jnr.1246
DO - 10.1002/jnr.1246
M3 - Article
C2 - 11746375
AN - SCOPUS:0035889473
SN - 0360-4012
VL - 66
SP - 559
EP - 564
JO - Journal of Neuroscience Research
JF - Journal of Neuroscience Research
IS - 4
ER -