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KMID : 0811720020060020109
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Korean Journal of Physiology & Pharmacology
2002 Volume.6 No. 2 p.109 ~ p.112
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The Regulation of AP-1 DNA Binding Activity by Long-term Nicotine Stimulation in Bovine Adrenal Medullary Chromaffin Cells Role of Second Messengers
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Hong Won Suh/Jin Koo Lee
Seong Soo Choi/Hong Won Suh
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Abstract
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The signal pathways involved in the regulation of AP-1 DNA binding activity in long-term nicotine stimulated bovine adrenal medullary chromaffin (BAMC) cells have not been well characterized. To understand the involvement of second messengers in the regulation of AP-1 DNA binding activity, the present study was designed to define the time-course for inhibition of nicotine-induced responses by cholinergic antagonists, Ca2+ and calmodulin (CaM) antagonists, and calcium/calmodulin-dependent protein kinase (CaMK) II inhibitor using electrophoretic mobility shift assay. Nicotine (10μM) stimulation increased AP-1 DNA binding activity at 24 hr after treatment. Posttreatment with hexamethonium (1 mM) plus atropine (1μM) (HA), nimodipine (1μM), or calmidazolium (1μM) at 0.5, 3, and 6 hr after the nicotine treatment significantly inhibited the AP-1 DNA binding activity increased by long-term nicotine stimulation. However, posttreatment with HA, nimodipine, or calmidazolium at 9 or 12 hr after the nicotine treatment did not affect the nicotine-induced increase of AP-1 DNA binding activity. The pretreatment of BAMC cells with various concentrations of KN-62 inhibited the increase of AP-1 DNA binding activity induced by nicotine in a concentration-dependent manner. KN-62 (10μM) posttreatment beginning at 0.5, 3, or 6 hr after the nicotine treatment significantly inhibited the increase of AP-1 DNA binding activity. However, KN-62 posttreatment beginning at 9 or 12 hr after the nicotine treatment did not affect the increase of AP-1 DNA binding activity. This study suggested that stimulation (for at least 6 hr) of nicotinic receptors on BAMC cells was necessary for increase of AP-1 DNA binding activity, and activation of Ca2+, CaM, and CaMK II up to 6 hr at least seemed to be required for the increase of nicotine-induced AP-1 DNA binding activity.
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KEYWORD
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AP-1 DNA binding activity, Bovine adrenal medullary chromaffin cells, Nicotine, Second messenger,
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