Articles: histamine.
-
Comparative Study Clinical Trial
Enhanced histamine metabolism: a comparative analysis of collagenous colitis and food allergy with respect to the role of diet and NSAID use.
To compare clinical data and histamine metabolism of patients with collagenous colitis with those of food allergy. ⋯ Histamine is extensively produced and metabolised in patients with collagenous colitis. In contrast to food allergy, the allergenic potency of the administered food seems not to influence histamine production in collagenous colitis. However, histamine metabolism corresponds with the clinical activity in both patients with food allergy and collagenous colitis.
-
The ability of allergens to induce hyperalgesia in immunoglobulin E (IgE)-sensitized rats was investigated. The left hind paws of Wistar rats were sensitized with intraplantar injections of IgE anti-dinitrophenylated bovine serum albumin monoclonal antibody, and challenged with dinitrophenylated bovine serum albumin 24 h later. Allergen challenge yielded rapid thermal hyperalgesia and oedema formation in the ipsilateral paws, both reaching a plateau from 15 min to 3 h, and both diminishing thereafter. ⋯ Anaphylactic hyperalgesia was mimicked by the combined administration of histamine, 5-hydroxytryptamine and bradykinin at doses which were ineffective when injected alone. This synergistic effect was abolished by treatment with either meclizine, methysergide, Hoe 140 or des-Arg(9)-[Leu(8)]-bradykinin. Our findings show that local thermal hyperalgesia is a feature of allergen-evoked inflammation, and that a synergistic interaction among bradykinin, 5-hydroxytryptamine and histamine plays a critical role in this phenomenon.
-
Anaphylactic shock accidents after allergen exposure are frequent. After immunization with ovalbumin (OVA), a common dietary constituent, we evaluated the efficacy of pretreatment with histamine-receptor or serotonin-receptor blockers administered alone or in combination with a nitric oxide synthase inhibitor (L-NAME) on OVA-induced anaphylactic shock in Brown Norway rats. Animals were allocated to the following groups (n = 6 each): control (0.9% saline); diphenydramine (15 mg kg(-1)); cimetidine (20 mg kg(-1)); diphenydramine + cimetidine; dihydroergotamine (50 microg kg(-1)); diphenydramine + cimetidine + dihydroergotamine; L-NAME (100 mg/kg) alone or associated with diphenydramine, cimetidine, diphenydramine + cimetidine, dihydroergotamine, or diphenydramine + cimetidine + dihydroergotamine. ⋯ Decreased vasodilatory (prostaglandins E2), increased vasoconstrictory (thromboxane B2) prostaglandins, and unchanged leukotriene C4 concentrations were contributory to the overall hemodynamic changes. Thus, the combined blockade of vasodilator mediators (histamine, serotonin, and nitric oxide) slowed the MABP drop in anaphylactic shock, but did not improve survival. More studies are needed to understand these discordant effects.
-
Bull. Exp. Biol. Med. · Jan 2003
Ultralow doses of antibodies to inflammatory mediators: antitussive properties of antibodies to bradykinin, histamine, and serotonin.
We studied antitussive activity of antibodies to inflammatory mediators (bradykinin, histamine, and serotonin) in ultralow doses. Experiments were performed on guinea pigs with cough induced by citric acid and capsaicin. ⋯ Antibodies to bradykinin in ultralow doses were most potent in relieving capsaicin-induced cough (up to 85%); antibodies to serotonin and, particularly, to histamine produced a smaller effect. Potentiated histamine and serotonin possessed polymodal properties.
-
Biochem. Biophys. Res. Commun. · Feb 2002
Orexins activate histaminergic neurons via the orexin 2 receptor.
Orexins (orexin A and B) are recently identified neuropeptides implicated in the regulation of vigilance states and energy homeostasis. We have shown here the physiological significance of histaminergic neurons in the orexin-induced arousal responses. Immunohistochemical and electron microscopic techniques revealed direct synaptic interaction between orexin-immunoreactive nerve terminals and histidine decarboxylase-immunoreactive neurons in the TMN. ⋯ Simultaneously recordings of electroencephalograph and electromyograph showed that intracerebroventricular infusion of orexin A significantly increased the awake state in the light phase. Central application of pyrilamine significantly inhibited this response. These results strongly suggest that activation of histaminergic neurons by orexins might be important for modulation of the arousal.