Abstract
The effect of histamine on the expression in vitro of C2, factor B and C3 genes in murine resident peritoneal macrophages was investigated. By measuring the levels of specific mRNA and the amount of the biosynthetically labelled gene products, we found that histamine decreases the biosynthesis of C2 and factor B. However, histamine had virtually no effect on the biosynthesis of C3 in the same cells. To clarify the mechanism of these effects, the H1 agonists (2-pyridylethylamine (PEA)and 2-methylhistamine), the H2-agonists (impromidine and 4-methyl-histamine), the H1-antagonist (chlorpheniramine) as well as the H2-antagonist (cimetidine) were also tested. We found that the inhibitory effect of histamine on C2 and factor B is produced only through H2 receptors. With the combination of histamine agonists and antagonists an inverse effect via H1- or H2-receptors was determined on the biosynthesis of C3. H1-receptor stimuli enhanced, and the stimulation of H2-receptors inhibited, C3 biosynthesis. All effects were pretranslational since the same results were obtained on mRNA and protein levels.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.