Premium
The role of calcium in the cyclic AMP response to histamine in rabbit cerebral cortical slices
Author(s) -
AlGadi M.,
Hill S.J.
Publication year - 1987
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1987.tb09001.x
Subject(s) - histamine , egta , calcium , agonist , medicine , adenosine , endocrinology , incubation , chemistry , stimulation , receptor , biology , biochemistry
1 The effect of calcium on the H 1 ‐and H 2 ‐receptor components of the cyclic AMP response to histamine in rabbit cerebral cortical slices has been investigated. 2 Removal of calcium ions from the incubation medium during the preparation, preincubation and final incubation of brain slices significantly reduced the cyclic AMP responses to adenosine, histamine and the H 2 ‐selective agonist, impromidine. 3 Removal of calcium ions from the incubation medium during only the final incubation with agonists did not influence the responses to adenosine, histamine, impromidine and the H 1 ‐selective agonist, 2‐thiazolylethylamine. 4 Final incubation of rabbit cerebral cortical slices in calcium‐free buffer containing EGTA (1 m m ) however, selectively reduced the cyclic AMP responses to the H 1 ‐agonists histamine and 2‐thiazolylethylamine without affecting the response to impromidine or adenosine. 5 These latter incubation conditions significantly reduced the maximal extent of the augmentation of impromidine‐or adenosine‐stimulated cyclic AMP accumulation produced by H 1 ‐receptor stimulation, without affecting the EC 50 values of the H 1 ‐agonists. Calcium‐free/EGTA conditions did not, however, alter the dose‐response parameters for the response to the H 2 ‐agonist, impromidine. 6 These data provide further evidence that the two histamine receptor systems affect cyclic AMP accumulation in rabbit cerebral cortical slices by different mechanisms.