Objective: Determining the possible effects of nitric oxide (NO) on histamine H3 receptor mediated contractile responses on gastric fundus smooth muscle.
Material and Methods: Isolated rat gastric fundus preparations were mounted on isolated organ bath. Histamine receptor agonist and antagonists were added to the bath solution, then the electrical field stimulation (EFS) induced contractile responses were evaluated.
Results: In our study groups after blocking the histamine receptors H1 by Pyrilamine (10-6?) and H2 by Famotidine (10-6?); contractile responses given to the histamine H3 receptor agonist (R)-α-methylhistamine (RAMH) on (10-8- 10-5? ) molar concentrations were observed. The same protochol was carried out to view the changes in the presence of NO precursore L-arginin (L-Arg)(10-4?, NO synthase inhibitor L-nitro-arginine-methyl ester (L-NAME) (10-4?) and combination of them.
Conclusion: It was concluded that there were no significant effect of NO on the contractile responses of histamine receptors since the presence of NO precursore L-Arg (10-4?) and NO synthase inhibitor L-NAME (10-4? ) and combination of them made no differences in the contractile responses.
Key Words: Histamine H3 receptor, Nitric oxide, Gastric fundus (R)-Α-Methylhistamine, Contractility, Electrical field stimulation.
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