title: Role of histamine receptors in the effects of histamine on the production of reactive oxygen species by whole blood phagocytes.
abstract: OBJECTIVE
  The diverse physiological functions of histamine are mediated through distinct histamine receptors. In this study we investigated the role of H2R and H4R in the effects of histamine on the production of reactive oxygen species by phagocytes in whole blood.
  
  
  METHODS
  Changes in reactive oxygen species (ROS) production by whole blood phagocytes after treatment with histamine, H4R agonists (4-methylhistamine, VUF8430), H2R agonist (dimaprit) and their combinations with H4R antagonist (JNJ10191584) and H2R antagonist (ranitidine) were determined using the chemiluminescence (CL) assay. To exclude the direct scavenging effects of the studied compounds on the CL response, the antioxidant properties of all compounds were measured using several methods (TRAP, ORAC, and luminol-HRP-H2O2 based CL).
  
  
  RESULTS
  Histamine, 4-methylhistamine, VUF8430 and dimaprit inhibited the spontaneous and OZP-activated whole blood CL in a dose-dependent manner. On the other hand, only VUF8430 was able to inhibit PMA-activated whole blood CL. Ranitidine, but not JNJ10191584, completely reduced the effects of histamine, 4-methylhistamine and dimaprit. The direct scavenging ability of tested compounds was negligible.
  
  
  CONCLUSIONS
  Our results demonstrate that the inhibitory effects of histamine on ROS production in whole blood phagocytes were caused by H2R. Our results also suggest that H4R agonists in concentrations higher than 10(-6)M may also influence ROS production via binding to H2R.
authors: Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, 612 65 Brno, Czech Republic.
authors: Ondrej
authors: O
authors: Vasicek
authors: Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, 612 65 Brno, Czech Republic.
authors: Antonin
authors: A
authors: Lojek
authors: Institute of Experimental Pharmacology & Toxicology, Slovak Academy of Sciences, Dubravska cesta 9, 841 04 Bratislava, Slovak Republic.
authors: Viera
authors: V
authors: Jancinova
authors: Institute of Experimental Pharmacology & Toxicology, Slovak Academy of Sciences, Dubravska cesta 9, 841 04 Bratislava, Slovak Republic.
authors: Radomir
authors: R
authors: Nosal
authors: Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, 612 65 Brno, Czech Republic. Electronic address: milanciz@ibp.cz.
authors: Milan
authors: M
authors: Ciz
mesh_terms: D001562:Benzimidazoles / Q000494:pharmacology; D017259:Dimaprit / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D006632:Histamine / Q000502:physiology*; D017442:Histamine Agonists / Q000494:pharmacology; D006801:Humans; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology; D010586:Phagocytes / Q000187:drug effects / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000097:blood*; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000378:metabolism*; D011968:Receptors, Histamine / Q000378:metabolism*; D011970:Receptors, Histamine H2 / Q000378:metabolism*; D000074040:Receptors, Histamine H4; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D001562:Benzimidazoles; D006146:Guanidines; C418607:HRH4 protein, human; D017442:Histamine Agonists; C506811:JNJ 10191584; D008761:Methylhistamines; D017382:Reactive Oxygen Species; D043562:Receptors, G-Protein-Coupled; D011968:Receptors, Histamine; D011970:Receptors, Histamine H2; D000074040:Receptors, Histamine H4; C516215:S-(2-guanidylethyl)isothiourea; C025566:4-methylhistamine; D006632:Histamine; D013890:Thiourea; D017259:Dimaprit
keywords: H(2)R; H(4)R; Histamine; Histamine receptors; Phagocytes; Reactive oxygen species