Subject: Why does my tongue get numb when I eat celery?

Hi... When I eat celery (say, about 2 sticks of standard celery-stick 
length, if I may use that measure) my tongue gets quite numb.  I have 
recently found out that this also happens to my mum.  No one else has ever 
heard of this, and thinks I'm fairly insane.  I'm in Molecular Biology & 
Biochemistry (3rd year) so I'd appreciate some guidance to a source where 
I might find some recepter/ligand actions to explain this odd relationship 
that my tongue seems to have with celery.  Thanking you very much in 
advance.  :)  

Re: Why does my tongue get numb when I eat celery?