[Konstantinos]

pawn Код:

new
    something
;

public OnGameModeInit( )
{
    something = 0; // 0 = closed
    return 1;
}

CMD:gates( playerid, params[ ] )
{
    if( something == 0 ) // if it's closed
    {
        // MoveObject( ... );
        something = 1; // 1 = opened
    }
    else // if it's opened
    {
        // MoveObject( ... );
        something = 0; // 0 = closed
    }
    return 1;
}

But in some cases, it's just for a certain playerid, so it should be with [ MAX_PLAYERS ] array.