A recent email suggested
nigra and
nigral, explaining -
The part of the brain that is damaged in Parkinson's disease is the substantia nigra. These are the cells that produce dopamine and project into the basal ganglia. In my profession nigra and nigral are commonly and widely used (I am a neurophysiologist). I wouldn't argue for this except for its relationship to Parkinsonism. That disorder is known widely enough to at least make this a rare word.
I think these are borderline cases. I couldn't find
nigral in any general dictionary, although there is an entry in Merriam-Webster's Medical Dictionary:
of, relating to, or being the substantia nigra <nigral cell firing>
Most of the examples using
nigral that I could find in Google Book Search were in medical journals or textbooks. One of the less specialised examples was in a magazine called
Texas Alcade (published by the Ex-Students' Association of Texas University) in 1992: "Parkinson's patients have only 60,000 to 120,000 nigral cells, so their dopamine supply is much reduced." The word has also been used in some press releases from the Michael J Fox Foundation for Parkinson's Research.
I couldn't find any example of
nigra being used in this sense other than as part of the term substantia nigra. However, an entry in Miller and Keane's
Encyclopedia and Dictionary of Medicine and Nursing, 1972, implies that
nigra can be used by itself, as a shortened term:
nigra (ni'grah) [L. black] substantia nigra. adj., ni'gral.
Other medical dictionaries also cross reference
nigra back to
nigra substantia. Perhaps
nigra, as an informal term for
substantia nigra, is used mainly in speech, rather than in writing, where the full phrase is normally used. Hence the difficulty of finding usage examples.
The fact that a word is used mainly within a particular profession should not automatically rule it out from our list, especially when it is a sizable profession like medicine. But on the basis of the evidence summarised above,
nigral would seem to have a stronger case than
nigra. However nigra does have another meaning, as defined in the Shorter Oxford:
n. & a. US (chiefly Southern). Freq. derog. and considered racially offensive. M20. [Repr. a pronunc. Cf. NIGGA.] = NEGRO
On other occasions in the forum we have talked about the difference between
using and
mentioning a word. I would never use this word, with this meaning, in a sentence, but I accept that it is part of the English language.
On balance I think both these suggestions should be accepted in the puzzle.
