Composition of cerebral fluids in goats adapted to high altitude

Page 508: V. Fencl, R. A. Gabel, and D. Wolfe. "Composition of cerebral fluids in goats adapted to high altitude."

Page 510: In the supplementary tabulated data deposited as NAPS Document 03492, there are some misprints and computational inconsistencies in the data on HCO^–₃ and Cl^– fluxes, and a systematic error in the reported transependymal fluxes of lactate at sea level (SL) and at high altitude (HA). These data have been revised, and a corrected version of the supplementary tables has been deposited.

Page 511: Data presented in Table 4, giving parameters (±SE) of regressions of transependymal fluxes (y) of HCO^–₃ and Cl^– on the differences in concentrations of these ions between the inflow perfusate and in the goat's CSF (x), should read: Cl^– flux at SL: y = (0.39 ± 0.03)x – (0.09 ± 0.22), r = 0.94; at HA: y = (0.40 ± 0.05)x – (0.05 ± 0.26), r = 0.90; both y-intercepts not significantly different from zero; HCO^–₃ flux at SL: y = (0.37 ± 0.03)x + (0.25 ± 0.16), r = 0.92, y-intercept not significantly different from zero; at HA: y = (0.44 ± 0.04)x + (2.53 ± 0.26), r = 0.91, y-intercept significantly greater than zero (P<0.001, F test; value of x at y = 0 is –5.8 mmol/kg H₂O, with the upper 95% tolerance limit of –4.0 mmol/kg H₂O). All the significance tests give the same results as presented in Table 4. Thus the conclusions drawn from the data are unchanged.

The mean value (±SE) of the lactate fluxes at SL was –158 ± 0.06 µmol/min, and at HL –3.28 ± 0.17 µmol/min (not –0.09 ± 0.04 and –1.47 ± 0.17 µmol/min, respectively, as indicated on page 511). The negative transependymal flux (washout of lactate) at HA was significantly greater than at SL (P<0.005, t test for independent means). It was twice as great at HA than at SL, rather than 16 times higher, as indicated in the Abstract and on page 512.

Page 512, column 2, paragraph 1: To interpret the data, it is suggested that "in goats adapted to HA, there exists a steady-state concentration gradient of [HCO^–₃] ..., with a lower [HCO^–₃] in cerebral ISF than in CSF," which "may be, at least in part, owing to a concentration gradient of lactate going in the opposite direction." This interpretation remains unchanged by the correction in lactate fluxes: The mean (±SE) increase in negative transependymal flux (washout) of lactate associated with adaptation to HA was 1.72 ± 0.28 µmol/min, which accounted for 68% of the mean positive transependymal flux of HCO^–₃ (2.53 ± 0.26 µmol/min, see above) in goats adapted to HA, when the ventriculocisternal system was perfused with fluid having bicarbonate concentration equal to that normally found in the goats' cisternal CSF. Thus, the conclusion that the "the fluid surrounding the central chemoreceptors appears to be more acidic in goats acclimatized to HA than at SL despite the alkalosis in cisternal CSF" continues to be substantiated by the corrected data.