[Studies on the contractile mechanism of isolated gastric smooth muscle cells of guinea pig--investigation of the histamine receptor].Nihon Shokakibyo Gakkai Zasshi. 1990 Dec; 87(12):2579-86.NS
Investigation about the histamine receptors of gastric smooth muscle cells was done using isolated gastric smooth muscle cells of guinea pig. Isolated gastric smooth muscle cells were prepared from the stomach of guinea pig by percoll density gradient centrifugation after enzymatic digestion with collagenase and dyspase. Contraction of the cells was determined by image of phase-contrast microscopy and digitizer and expressed as the mean per cent of control in cell axis length. The concentration of intracellular Ca2+ ([Ca2+]i) was measured with the calcium-sensitive dye fura-2. Tested drugs were added to the incubation medium containing 2 mM CaCl2. Both contractile response and [Ca2+]i increased following histamine stimulation in a dose-dependent manner from 10(-7) to 10(-4) M, and those peaks were obtained in application of 10(-4) M pyridylethylamine, a H1 receptor agonist, made an increase in [Ca2+]i as much as 10(-4) M histamine. But 10(-4) M dymaprit, a H2 receptor agonist, made only small increase in [Ca2+]i, whose value was similar to that in application of only 2 mM CaCl2. 10(-4) M pyrilamine, a H1 receptor antagonist, inhibited the response to 10(-4) M histamine, and the value was similar to that in application of only 2 mM CaCl2. Cimetidine, a H2 receptor antagonist, did not inhibit the response to 10(-4) M histamine stimulation at all. From those results it is concluded that the action of histamine to the gastric smooth muscle cells of guinea pig may be mediated through H1 receptor, but not through H2 receptor.