Effect of trimethyllead chloride on slowly activating (SV) channels in red beet (Beta vulgaris L.) taproots

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• 作者：Zenon Trela^a ; Zbigniew Burdach^b ; Stanis?aw Przestalski^a ; Waldemar Karcz^b ; ^{waldemar.karcz@us.edu.pl}
• 关键词：Beta vulgaris ; Current SV channels ; Trimethyllead chloride ; Vacuole
• 刊名：Comptes Rendus Biologies
• 出版年：2012
• 出版时间：December, 2012
• 年：2012
• 卷：335
• 期：12
• 页码：722-730
• 全文大小：893 K

文摘

The patch-clamp technique was used to examine the effect of trimethyllead chloride (Met₃PbCl) on SV channel activity in red beet (Beta vulgaris L.) taproot vacuoles. It was found that in the control bath the macroscopic currents showed the typical slow activation and a strong outward rectification of the steady-state currents. An addition of Met₃PbCl to the bath solution blocked, in a concentration-dependent manner, SV currents in red beet vacuoles. The time constant ¦Ó increased several times in the presence of 100 ¦ÌM trimethyllead chloride at all voltages tested. When single channel properties were analyzed, only little channel activity could be recorded in the presence of 100 ¦ÌM Met₃PbCl. Trimethyllead chloride decreased significantly (by about one order of magnitude) the open probability of single channels. The recordings of single channel activity obtained in the presence and absence of Met₃PbCl showed that organolead only slightly (by ca. 10 % ) decreased the unitary conductance of single channels. It was also found that Met₃PbCl diminished significantly the number of SV channel openings, whereas it did not change the opening times of the channels. Taken together, these results suggest that Met₃PbCl binding site is located outside the channel selectivity filter.