Foreman JC, Norris DB, Rising TJ, Webber SE. A study of the H2-receptor for histamine stimulating adenylate cyclase in homogenates of guinea-pig lung parenchyma.
Br J Pharmacol 1986;
87:37-44. [PMID:
2869813 PMCID:
PMC1916899 DOI:
10.1111/j.1476-5381.1986.tb10154.x]
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Abstract
The effect of forskolin and several H2-agonists was investigated on the activity of adenylate cyclase in homogenates of guinea-pig lung parenchyma. Histamine, 0.1 microM to 1 mM, dimaprit, 1 microM to 10 mM, 4-methyl histamine, 0.1 microM to 10 mM, impromidine, 10 nM to 10 microM and forskolin, 1 nM to 100 microM, all produced a dose-dependent stimulation of adenylate cyclase activity above the basal level. The histamine H1-receptor antagonist mepyramine, 10 microM, and beta-adrenoceptor antagonist propranolol, 10 microM, had no effect on the stimulation by histamine of adenylate cyclase. The dose-response curve for stimulation by histamine of adenylate cyclase was shifted to the right in a dose-dependent manner by increasing concentrations of several H2-antagonists. Schild plots constructed for each H2-antagonist produced straight lines with slopes not significantly different from unity. The equilibrium dissociation constants obtained for the H2-antagonists in this study were similar to those previously reported for inhibition of dimaprit-induced relaxation of the pre-contracted lung strip, inhibition of [3H]-tiotidine binding to homogenates of guinea-pig lung parenchyma and inhibition of histamine-stimulated adenylate cyclase in guinea-pig gastric mucosa.
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