Several years ago, we reported a high frequency of
cataracts in Dahl salt-sensitive rats (DS) which led us to carry out a series of studies, such as longitudinal
ouabain-sensitive lens 86Rb uptake measurements. Yet, throughout all of our work, we used the Dahl
salt-resistant rat (DR) as our control group, despite the fact that DR is a strain resistant to even experimental
hypertension such as that resulting from renal
cellophane wrapping. Thus, in the present study we assessed lens short-circuit current (Isc) in adult Sprague-Dawley rats (SD) from which DS and DR were derived. Sprague-Dawley rats were studied during chronic normal vs high NaCl intake. These studies showed that basal Isc and calculated translenticular potential difference (
PDt) were nearly doubled by this dietary regimen. Sequential addition of
BaCl2 and
ouabain to the isolated lens anterior surface bath also revealed increased BaCl2-sensitive as well as BaCl2- and
ouabain-insensitive lens Isc in SD kept on a high NaCl diet. There was a statistically insignificant tendency for lens
ouabain-sensitive Isc to increase in SD given a high NaCl diet. These findings were unrelated to levels of arterial blood pressure which were not altered by chronic high NaCl intake in adult SD. Our data suggest the possibility of increased lens
barium and
ouabain insensitive ionic permeabilities combined with possibly increased lens fiber
potassium concentration, as a response to chronic high dietary NaCl in the normal rat. The nature of the
barium and
ouabain insensitive component of the lens Isc that rises during chronic high NaCl intake requires elucidation.(ABSTRACT TRUNCATED AT 250 WORDS)