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Effects of adenosine receptor agonists on volume‐activated ion transport in pig red cells
Author(s) -
Sohn Dong Hwan,
Kim Hyun Dju
Publication year - 1991
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041460217
Subject(s) - adenosine , chemistry , adenosine receptor , agonist , biophysics , intracellular , ion transporter , ouabain , receptor , stimulation , flux (metallurgy) , adenosine a1 receptor , medicine , endocrinology , biochemistry , sodium , biology , membrane , organic chemistry
Abstract Swelling of pig red cells leads to an increase in a chloride‐dependent K flux which can be potentiated by cAMP, whereas cell shrinking causes a selective increase in Na movement which is mediated by a Na/H exchanger. We examined the influence of adenosine and adenosine receptor agonists on the volume‐sensitive, ouabain‐resistant, chloride‐dependent K flux, referred to as Rb flux and volume‐activated Na/H exchange pathway. It was found that adenosine and adenosine receptor agonists inhibited the Rb flux. N 6 ‐cyclohexyl adenosine (CHA) has been found to be the most potent inhibitor with EC 50 of approximately 4.5 μM followed by 2‐chloroadenosine (Cl‐ado) with EC 50 of approximately 27 μM and 5′‐(N‐ethyl)‐carboxamido‐adenosine (NECA) with EC 50 of approximately 185 μM. CHA also inhibits the cAMP‐stimulated Rb flux. However, CHA does not alter the basal intracellular cAMP level nor the intracellular cAMP content raised by exogenously added cAMP. In contrast to the adenosine agonist action on the Rb flux, Na/H exchange, which is activated upon cell shrinkage, exhibits a slight stimulation in response to CHA. These findings suggest that the presence of A 1 adenosine receptors on the surface of red cells influences the regulation of volume‐activated ion transport.