Abstract
A sudden decrease in external medium osmolality (90 mosmol/kg) causes an immediate swelling of trout erythrocytes, followed by a regulatory volume decrease (RVD) due to activation of both a KCl cotransporter and a taurine transport pathway. Here, we determined how trout red cells respond when they are exposed to a gradual and slow decrease in medium osmolality (80 mosmol/kg at a rate of 0.7 mosmol/kg per min). Erythrocytes were unable to regulate their volume efficiently when swollen gradually and it increased continuously throughout the experimental period (120 min). As long as volume was increased slowly by 15–25%, regulatory pathways remained essentially inactivated, erythrocytes losing no significant amount of intracellular osmotically active solutes. Above this swelling threshold, a response was triggered but the quantity of solutes lost via the regulatory pathways was still not sufficient to counterbalance the continuous entry of water due to the slow and gradual decrease in medium tonicity.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 18 January 1999 / Received after revision: 10 February 1999 / Accepted: 11 February 1999
Rights and permissions
About this article
Cite this article
Godart, H., Ellory, J. & Motais, R. Regulatory volume response of erythrocytes exposed to a gradual and slow decrease in medium osmolality. Pflügers Arch 437, 776–779 (1999). https://doi.org/10.1007/s004240050845
Issue Date:
DOI: https://doi.org/10.1007/s004240050845