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Updated: Jul 26, 2026

Isolation of Atrial Myocytes from Adult Mice
Published on: July 25, 2019
Antagonistic activity of tiotidine and ranitidine on guinea-pig and rabbit atria
Abstract:
Isolated, spontaneously beating atrial pairs from rabbits and guinea-pigs were used to determine and to compare the activity of ranitidine and tiotidine as antagonists of histamine stimulated chronotropic activity. Ranitidine produced a classical competitive, reversible antagonism of histamine effects with a pA2 in rabbit atria of 8.2. In contrast, tiotidine produced both a dextral shift of the log dose-response curve, as well as a previously unreported suppression in the maximal response produced by histamine. In accordance with receptor theory, this type of activity represents a dualistic antagonism of histamine chronotropic responses.
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