下列属于第二信使的离子是（  ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='24966' and id < 2127223 and id<>'2127223' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='24966' and id > 2127223 and id<>'2127223' order by id asc limit 5