[Orgmode] Updating CONSTANTS in LaTeX mode

[Seweryn]

Hello,

Is it possible to have locally defined CONSTANTS in .tex buffer? What is the 
command to update the list of known CONSTANTS since $pi works but I cannot 
insert $x to the list of CONSTANTS. See example below

\begin{comment}
#+CONSTANTS: x=458.0
#+ORGTBL: SEND test1 orgtbl-to-latex :splice t :lend ""
| 3.1415927 | #ERROR |
#+TBLFM: @1$1=$pi::@1$2=$x
% $
\end{comment}

I would appreciate a hint.
Thanks.