Acid influx into snail neurones caused by reversal of the normal pHi‐regulating system.

Publisher Website
Google Scholar
Abstract
Intracellular pH (pHi), and Na+ and Cl- activities were measured with ion-sensitive micro-electrodes in H. aspersa neurons and the effects of reducing external pH (pHo) were investigated. When pHo was changed from 7.5 to 6.5 keeping CO2 constant, there was a slow fall in pHi, a rise in internal Cl and a fall in internal Na. These ionic changes are opposite to those caused by normal operation of the pHi-regulating system. These effects of external acidification were inhibited by the application of SITS (4-acetamiod-4''-isothiocyanatostilbene-2,2''-disulfonic acid) or by the removal of external Cl. Raising intracellular Na activity by inhibiting the Na pump increased the rate of fall in pHi in acid solutions. In acid solutions the average rate of acid uptake attributable to reversed pHi-regulation was about 3 times the rate of loss of internal Na, and about twice the rate of Cl uptake. Apparently, the intracellular ion changes in acid solutions are largely due to a reversal of the pHi-regulating mechanism, so that it carries acid into, rather than out, of the cell interior.

This publication has 1 reference indexed in Scilit: