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Introduction to dermatological treatment
Published in Richard Ashton, Barbara Leppard, Differential Diagnosis in Dermatology, 2021
Richard Ashton, Barbara Leppard
Antihistamines act as competitive blockers of histamine receptors. They have a close structural resemblance to histamine. As there are two types of histamine receptor, H1 and H2, there are two types of anti-histamines. Cutaneous blood vessels have both H1 and H2 receptors, but for skin disease H1 antihistamines are the most effective.
Pharmacotherapy of Neurochemical Imbalances
Published in Sahab Uddin, Rashid Mamunur, Advances in Neuropharmacology, 2020
Rupali Patil, Aman Upaganlawar, Suvarna Ingale
There are four subtypes of histamine receptors—H1, H2, H3, and H4 (Table 22.6). They are widely scattered centrally and in periphery. All four types of histamine receptors are GPCRs. H1 and H2 receptors are post-synaptic, located on neuroeffector junction. Unlike H1 and H2 receptors, H3 receptors are presynaptic, and prevent secretion of histamine and other transmitters via a G-protein. H4 receptors are located on blood cells like eosinophils, neutrophils, and CD4 T cells. Of the four types, H1 and H2 receptors, agonists, and antagonists have been studied extensively for targets of drug research (Barrett et al., 2009; Nestler et al., 2009).
IgE-mediated (immediate) hypersensitivity
Published in Gabriel Virella, Medical Immunology, 2019
Albert F. Finn, Gabriel Virella
In many cases, the appearance of eosinophils signals the onset of internal negative feedback and control mechanisms that terminate the immediate hypersensitivity reaction. This effect is associated with the production and release of enzymes, particularly histaminase (which degrades histamine) and phospholipase D (which degrades PAF). Active oxygen radicals released by stimulated granulocytes, including eosinophils and perhaps neutrophils (which are also attracted by ECF-A and LTB4), cause the breakdown of leukotrienes. Histamine itself can contribute to the downregulation of the allergic reaction by binding to a type II histamine receptor expressed on basophils; the occupancy of this receptor leads to an intracellular increase in the level of cAMP, which inhibits further release of histamine (negative feedback).
Burden of adult atopic dermatitis and unmet needs with existing therapies
Published in Journal of Dermatological Treatment, 2023
Elizabeth D. Bacci, Julia R. Correll, Evangeline J. Pierce, Amber Reck Atwater, Zach Dawson, Wendy Smith Begolka, Lisa Butler
In the current study, the most-used current systemic treatments were oral antihistamines. However, evidence on efficacy of antihistamines as a part of AD treatment is insufficient (15,27–30). In addition, blocking histamine receptors does not lead to significant improvement in itch or inflammation associated with AD (31). This could be a reason for lower treatment satisfaction among patients with AD. In a recent retrospective study of adult patients with AD, 21.1% of those receiving topical therapy and 30.8% receiving topical + systemic therapy were ‘less than satisfied’ with their current AD treatments (20), suggesting an unmet need in patients using either topical or both topical and systemic treatments. Although this study did not compare TSQM scores of participants based on treatment category, participants on topical therapy scored numerically lower than those on systemic therapy. Moreover, in line with studies from Japan and the US (19,32), the lowest treatment satisfaction was observed in participants with severe AD. These findings emphasize the need for effective treatments in patients with more severe AD. Although new treatments have been recently approved for use (17), their effect in the real-world setting remains to be seen (33).
Trafficking of carbonic anhydrase 12 and bicarbonate transporters by histamine stimulation mediates intracellular acidic scenario in lung cancer cells
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Hyeong jae Kim, Jeong Hee Hong
Protein trafficking is mediated by involvement of endocytic process29. To confirm histamine receptor activation-mediated CA12 and AE2 trafficking and modulation of cellular pH, cells were treated bafilomycin A1 (Baf), which is an inhibitor of protein trafficking from early endosome and V-ATPase inhibitor30. To evaluate the trafficking of AE2 by histamine treatment, AE2 expression was determined with and without Baf. The histamine receptor activation-mediated enhanced membranous AE2 was reduced by Baf treatment (Figure 5(A,B)). In addition, treatment of Baf enhanced the surface expression of CA12 and restored the reduced CA12, which is attenuated by histamine (Figure 5(A,C)). Immunostaining image of CA12 revealed the restored surface expression of CA12 in presence of Baf (Figure 5(D)). Histamine treatment induced membranous expression of AE2 and the trafficking of AE2 towards membrane was inhibited by Baf (Figure 5(E)). Trafficking of AE2 was verified by the measurement of CBE activity. Histamine receptor activation-mediated CBE activity was attenuated by treatment of Baf (Figure 5(F,G)). The histamine receptor activation-mediated acidic cellular pH was also attenuated by Baf treatment (Figure 5(H,I)). NBC expression and activity were reduced by histamine receptor activation and Baf treatment did not restore the NBC expression (Supplementary Figure 7(A–C)). These results address that histamine receptor activation induced internalised CA12 and membranous AE2. Additionally, trafficking of CA12 and AE2 is involved in modulation of cellular pH.
Profiling plasma levels of thiamine and histamine in Jordanian children with autism spectrum disorder (ASD): potential biomarkers for evaluation of ASD therapies and diet
Published in Nutritional Neuroscience, 2023
Ayat Hussein B. Rashaid, Mazin Taha Alqhazo, Shreen Deeb Nusair, James B. Adams, Mahmoud Ahmad Bashtawi, O’la Al-Fawares
Histamine is associated with many neurological disorders including ASD. Antagonism of histamine receptors 1–3 reduced social behaviors in ASD patients and relevant animal models [1]. Histaminergic neurons are within the hypothalamus with diffuse projection in the spinal cord and the brain stem [1]. Histamine mediates neuroinflammation in ASD which increases microglia activation, and reduces connectivity of the frontal basal ganglia circuit leading to language processing abnormalities [1]. Histamine has other roles in cognition, sleep, attention, sensory/motor function, cytokine release/migration, phagocytosis and production of reactive oxygen species [1]. Considering the crucial roles of the selected biomarkers in ASD etiology, our study investigated the plasma levels of thiamine and histamine in children with ASD relative to their levels in age-and gender-matched healthy controls. This is the first study to investigate the potential use of these two biomarkers in ASD, and relate their levels to ASD severity. Monitoring of such biomarkers will provide further understanding of ASD etiology and will serve as a platform for future work toward developing ASD therapies.