[visionlist] protanopic cone

[Mickey Rowe;893-2446]

"Vitali Gavrik" <gavrik at arcor.de> asks:

> I hope you can help me. Do you know anybody who has performed the 
> following:
>    (1) microspectrophotometry of single protanopic cones;
>    (2) direct photoelectric measurements of the spectral sensitivity of 
> single protanopic cones?

It's not clear what you're looking for -- in the standard model of
congenital color deficiencies, a protanope is a human who is missing
all long-wave sensitive cones.  Thus a protanope's retina should
contain two cone types, the short and mid-wave sensitive cones.  If I
were to guess as to your intent it would be either that you want the
spectral sensitivity of the mid-wave sensitive cones (an assumption
dating back well over a century and largely confirmed through genetic
analyses is that protanopes generally have normal mid- and short-wave
sensitive cones).  My second guess is that you want to know about
protanomalous individuals, not protanopes, and hence you want to know
the spectral sensitivity of the abnormal long-wave sensitive cones.

If my first guess is correct, then there is a forty year history of
such measurements.  But probably the best place to start would be
here:

http://www.nature.com/nature/journal/v325/n6103/abs/325439a0.html

If I'm right in my second guess, then I'm pretty sure that you will
not find exactly what you are looking for.  However, there are a lot
of absorption spectra measured from reconstituted photopigments.  Look
at this:

http://www.blackwell-synergy.com/doi/abs/10.1111/j.1399-0004.2004.00343.x

for a fairly recent review.

Hope that helps,

-- 
Mickey P. Rowe     (mrowe at lifesci.ucsb.edu)