Inversion of Ca2+ current modulation during recovery of neuroblastoma cells from pertussis toxin pretreatment

FEBS Letters

Friederich, P.¹  Schultz, G.¹  Nürnberg, B.¹  Hescheler, J.¹ 

[1] Pharmakologisches Institut, Freie Universität Berlin, Thielallee 69-73, D-14195 Berlin, Germany

关键词: Ca2+ channel current;    SH-SY5Y;    Neuroblastoma cell;    Opioid;    Pertussis toxin;    G-protein;    DAGO;    [d-Ala2;    N-Me-Phe4;    Gly5-ol]-enkephalin;    DPDPE;    [d-Pen2;    Pen5]-enkephalin;    TRH;    thyrotropin-releasing hormone;    DA;    dopamine;    SST;    somatostatin;    PTX;    pertussis toxin;    an exotoxin of Bordetella pertussis;    PI response;    phosphatidylinositol 4;    5-biphosphate hydrolysis;   

DOI  :  10.1016/0014-5793(93)80703-W

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Human neuroblastoma cells (SH-SY5Y) differentiated by retinoic acid exhibited high threshold-activated N-type Ca²⁺ currents, which were largely inhibited by the two enkephalins, DAGO and DPDPE, as well as by dopamine and somatostatin. The inhibitory effects were fully abolished after pretreatment of cells with pertussis toxin. After washing out the toxin, the inhibitory effects re-established with a time constant of about 16 h. The recovery of Ca²⁺ current inhibition was similar for all tested agonists. Unexpectedly, we observed a neurotransmitter-induced stimulation of Ca²⁺ currents in approximately 10% of all investigated cells during the recovery phase. Such a stimulatory effect by otherwise inhibitory receptors was never seen in control cells. It did also not occur when exogenous purified G-proteins of the G_i family were reconstituted via the patch pipette, suggesting that additional mechanisms may play a role in the appearance of stimulatory effects during the recovery phase after pertussis toxin pretreatment.

【 授权许可】

Unknown