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Genetic variability of histamine receptors in patients with Parkinson's disease
Elena García-Martín, P Ayuso, Antonio Luengo, Carmen Martínez, José AG Agúndez
BMC Medical Genetics , 2008, DOI: 10.1186/1471-2350-9-15
Abstract: Leukocytary DNA from 195 PD patients and a control group of 231 unrelated healthy individuals was studied for the nonsynonymous HRH1Leu449Ser and the promoter HRH2G-1018A polymorphisms by using amplification-restriction analyses.The HRH1Leu449Ser amino acid substitution was identified in two women with late-onset PD whereas it was not observed among healthy subjects. The HRH2G-1018A polymorphism was observed with allele frequencies = 3.59 (95% CI = 1.74–5.44) and 5.0 (95% CI = 3.00–6.96) for patients with PD and healthy controls, respectively. These frequencies were independent of gender and age of onset of the disease. Multiple comparison analyses revealed that differences were not statistically significant.These results indicate that the polymorphisms analyzed are not a major risk factor for PD, although the HRH1Leu449Ser amino acid substitution might be related to PD.Histamine is involved in neuronal degeneration [1] and neurotoxicity [2]. Changes in the morphology and increase in density of histaminergic fibers in the substantia nigra have been described in the brain of PD patients [3]. It has been shown that histamine causes selective damage in the dopaminergic neurons of the substantia nigra with induction of inflammatory signal processes [4]. Among patients with PD, blood histamine levels [5] and the concentration of the histamine metabolite pros-methylimidazoleatic acid in the cerebrospinal fluid are increased [6], and recently we described the association of genotypes leading to high histamine metabolism with increased risk to develop PD [7]. Taken together, these findings suggest that modulation of brain histamine may be related to PD, but the mechanisms underlying such modulation remains unknown.Changes in the density and expression of histamine receptors (HRH) have been detected in PD patients [8]. HRH antagonists bring about improvements in motor and other symptoms [9,10], thus suggesting that HRH play a role in the clinical response of PD patients. Sin
The Effects of Histamine H3 Receptors on Contractile Responses on Rat Gastric Fundus  [PDF]
A?k?n Hekimo?lu,Ramazan ?i?ek
Dicle Medical Journal , 2006,
Abstract: The aim of this study is to determine the effects of histamine receptors on the gastrointestinal system smooth muscle contractions and the role of histamine H3 receptors on these effects. solated rat gastric fundus preparations were hanged on isolated organ bath and histamine receptor agonist and anthagonists were added to the bath solution and the electrical field stimulation-induced contractile responses were evaluated. In our study groups after blocking one of the histamine receptors H1, H2,H3; contractile responses were observed. Then, other two receptors were blocked one by one or combination of them to observe the changes on the contractile responses given to the electrical stimulation .To blocke histamine receptors pyrilamine (10-6м) as H1 receptor blocker, famotidine (10-6м) as H2 receptor blocker and thioperamide (10-5м) as H3 receptor blocker and various combination of them were used. All groups were treated with H3 receptor anthagonist thioperamide (10-5м) and agonist (R)-α-methylhistamine (R)MHA on 10-8, 10-7, 10-6 ve 10-5 molar concentrations cumulatively to observe its mediator effects on contractile responses. We suggested that (R)-α-methylhistamine mediates the inhibition on the contractile effects of rat gastric fundus. This conclusion was supported by these findings: a) the selective agonists (R)MHA caused a dumping of the contractile effect of acetylcholine; b) the effect of (R)MHA was prevented by the selective H3 receptor antagonist thioperamide.
Hippocampal histamine receptors and conflictive exploration in the rat: studies using the elevated asymmetric plus-maze
Ruarte, M.B.;Orofino, A.G.;Alvarez, E.O.;
Brazilian Journal of Medical and Biological Research , 1997, DOI: 10.1590/S0100-879X1997001200012
Abstract: the possible role of histamine receptors in the hippocampal formation on the exploratory motivation and emotionality of the rat was studied. an elevated asymmetric plus-maze composed of 4 different arms (no walls, single high wall, high and low walls and two high walls) arranged at 90o angles was used. the exploration score, considered to be an index of exploratory motivation, and the permanency score, considered to be an index of emotionality (anxiety), were determined. histamine was administered locally into the ventral hippocampus at three different doses (9, 45 and 90 nmol). another group of rats was also microinjected with 45 nmol of pyrilamine (a histamine h1 receptor antagonist) or ranitidine (a histamine h2 receptor antagonist) in addition to 9 nmol of histamine in order to identify the possible type of histamine receptor involved. histamine administration significantly inhibited the exploration score and increased the permanency score at the doses of 9 and 45 nmol in two of four arms. these effects were completely blocked by the administration of either histamine receptor antagonist. the present results suggest that in the hippocampal formation histamine inhibits exploratory motivation and decreases emotionality by activating both types of histamine receptors. also, the elevated asymmetric plus-maze appears to be a suitable technique to quantify exploration and possibly" anxiety"
Hippocampal histamine receptors and conflictive exploration in the rat: studies using the elevated asymmetric plus-maze  [cached]
Ruarte M.B.,Orofino A.G.,Alvarez E.O.
Brazilian Journal of Medical and Biological Research , 1997,
Abstract: The possible role of histamine receptors in the hippocampal formation on the exploratory motivation and emotionality of the rat was studied. An elevated asymmetric plus-maze composed of 4 different arms (no walls, single high wall, high and low walls and two high walls) arranged at 90o angles was used. The exploration score, considered to be an index of exploratory motivation, and the permanency score, considered to be an index of emotionality (anxiety), were determined. Histamine was administered locally into the ventral hippocampus at three different doses (9, 45 and 90 nmol). Another group of rats was also microinjected with 45 nmol of pyrilamine (a histamine H1 receptor antagonist) or ranitidine (a histamine H2 receptor antagonist) in addition to 9 nmol of histamine in order to identify the possible type of histamine receptor involved. Histamine administration significantly inhibited the exploration score and increased the permanency score at the doses of 9 and 45 nmol in two of four arms. These effects were completely blocked by the administration of either histamine receptor antagonist. The present results suggest that in the hippocampal formation histamine inhibits exploratory motivation and decreases emotionality by activating both types of histamine receptors. Also, the elevated asymmetric plus-maze appears to be a suitable technique to quantify exploration and possibly" anxiety"
Changes in Histamine Receptors (H1, H2, and H3) Expression in Rat Medial Vestibular Nucleus and Flocculus after Unilateral Labyrinthectomy: Histamine Receptors in Vestibular Compensation  [PDF]
Liuqing Zhou, Wen Zhou, Sulin Zhang, Bo Liu, Yangming Leng, Renhong Zhou, Weijia Kong
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066684
Abstract: Vestibular compensation is the process of behavioral recovery following peripheral vestibular lesion. In clinics, the histaminergic medicine is the most widely prescribed for the treatment of vertigo and motion sickness, however, the molecular mechanisms by which histamine modulates vestibular function remain unclear. During recovery from the lesion, the modulation of histamine receptors in the medial vestibular nucleus (MVN) and the flocculus may play an important role. Here with the means of quantitative real-time PCR, western blotting and immunohistochemistry, we studied the expression of histamine receptors (H1, H2, and H3) in the bilateral MVN and the flocculus of rats on the 1st, 3rd, and 7th day following unilateral labyrinthectomy (UL). Our results have shown that on the ipsi-lesional flocculus the H1, H2 and H3 receptors mRNA and the protein increased significantly on the 1st and 3rd day, with compare of sham controls and as well the contralateral side of UL. However, on the 7th day after UL, this expression returned to basal levels. Furthermore, elevated mRNA and protein levels of H1, H2 and H3 receptors were observed in the ipsi-lesional MVN on the 1st day after UL compared with sham controls and as well the contralateral side of UL. However, this asymmetric expression was absent by the 3rd post-UL. Our findings suggest that the upregulation of histamine receptors in the MVN and the flocculus may contribute to rebalancing the spontaneous discharge in bilateral MVN neurons during vestibular compensation.
Calyx and dimorphic neurons of mouse Scarpa's ganglion express histamine H3 receptors
Simona Tritto, Laura Botta, Valeria Zampini, Gianpiero Zucca, Paolo Valli, Sergio Masetto
BMC Neuroscience , 2009, DOI: 10.1186/1471-2202-10-70
Abstract: RT-PCR analysis showed the presence of H3 receptor mRNA in mouse ganglia tissue. H3 protein expression was found in vestibular neurons characterized by large and roundish soma, which labeled for calretinin and calbindin.The present results are consistent with calyx and dimorphic, but not bouton, afferent vestibular neurons expressing H3 receptors. This study provides a molecular substrate for the effects of histamine-related antivertigo drugs acting on (or binding to) H3 receptors, and suggest a potential target for the treatment of vestibular disorders of peripheral origin.The vestibular, or balance, organs inform the brain about the movements and position of the head. The sensory receptors of the vestibular apparatus are the hair cells. Two types of hair cells are present in mammalian vestibular organs, called Type I and Type II hair cells, which differ substantially in their afferent contact. The Type I hair cell's basolateral membrane is completely enveloped in a large afferent nervous terminal, called a calyx. In contrast, Type II hair cells are contacted by numerous bouton-like afferent terminals. The soma of afferent neurons are located in the Scarpa's ganglion. Central projections of the vestibular nerve contact secondary neurons located in the brainstem (vestibular nuclei) and in the cerebellum, which provide the anatomical basis for the vestibular reflexes.Most cases of dizziness and vertigo are due to problems in vestibular organs, presumably resulting in wrong afferent signaling interpreted by the brain as if the head is moving or turning when it is actually not.Among the pharmacological compounds commonly used in the symptomatic treatment of vertigo and related vestibular disorders are histamine-related drugs, such as promethazine [1], dimenhydrinate [2] and cinnarizine [3], assumed to act at H1 histamine receptors, and betahistine [4,5], which has been shown to act as an H3 histamine receptor antagonist [6]. However, the site/s of action of these drugs
Plasticity of the histamine H3 receptors after acute vestibular lesion in the adult cat  [PDF]
Brahim Tighilet,Michel Lacour
Frontiers in Integrative Neuroscience , 2014, DOI: 10.3389/fnint.2013.00087
Abstract: After unilateral vestibular neurectomy (UVN) many molecular and neurochemical mechanisms underlie the neurophysiological reorganizations occurring in the vestibular nuclei (VN) complex, as well as the behavioral recovery process. As a key regulator, the histaminergic system appears to be a likely candidate because drugs interfering with histamine (HA) neurotransmission facilitate behavioral recovery after vestibular lesion. This study aimed at analyzing the post-lesion changes of the histaminergic system by quantifying binding to histamine H3 receptors (H3R; mediating namely histamine autoinhibition) using a histamine H3 receptor agonist ([3H]N-α-methylhistamine). Experiments were done in brain sections of control cats (N = 6) and cats submitted to UVN and killed 1 (N = 6) or 3 (N = 6) weeks after the lesion. UVN induced a bilateral decrease in binding density of the agonist [3H]N-α-methylhistamine to H3R in the tuberomammillary nuclei (TMN) at 1 week post-lesion, with a predominant down-regulation in the ipsilateral TMN. The bilateral decrease remained at the 3 weeks survival time and became symmetric. Concerning brainstem structures, binding density in the VN, the prepositus hypoglossi, the subdivisions of the inferior olive decreased unilaterally on the ipsilateral side at 1 week and bilaterally 3 weeks after UVN. Similar changes were observed in the subdivisions of the solitary nucleus only 1 week after the lesion. These findings indicate vestibular lesion induces plasticity of the histamine H3R, which could contribute to vestibular function recovery.
Synthesis of Peptides Histamine H2 Receptors in Solid-Phase Assisted by Microwave
Reynoso-Soto, Edgar A.;Rivero, Ignacio A.;
Journal of the Mexican Chemical Society , 2010,
Abstract: the synthesis of histamine h2 receptors peptides was conducted using the methodology of solid phase assisted by microwaves. microwaves can reduce the reaction times during the coupling and deprotection steps to obtain the desired peptide sequence. the coupling reaction was carried out with a mixture of n, n'-diisopropyl-carbodiimide (dic) and n,n,n'n'-tetramethyl-o-(1h-benzotriazol-1-yl)uronium hexafluorophosphate (hbtu). the purity and yield are improved in peptide synthesis assisted by microwaves. coupling reactions and deprotection on rink resin were carried out in 5 min depending on amino acid and the length of the peptide chain.
Kv4.2 Mediates Histamine Modulation of Preoptic Neuron Activity and Body Temperature  [PDF]
Jasmine Sethi, Manuel Sanchez-Alavez, Iustin V. Tabarean
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0029134
Abstract: Histamine regulates arousal, circadian rhythms, and thermoregulation. Activation of H3 histamine receptors expressed by preoptic GABAergic neurons results in a decrease of their firing rate and hyperthermia. Here we report that an increase in the A-type K+ current in preoptic GABAergic neurons in response to activation of H3 histamine receptors results in decreased firing rate and hyperthermia in mice. The Kv4.2 subunit is required for these actions in spite of the fact that Kv4.2?/? preoptic GABAergic neurons display A-type currents and firing characteristics similar to those of wild-type neurons. This electrical remodeling is achieved by robust upregulation of the expression of the Kv4.1 subunit and of a delayed rectifier current. Dynamic clamp experiments indicate that enhancement of the A-type current by a similar amount to that induced by histamine is sufficient to mimic its robust effect on firing rates. These data indicate a central role played by the Kv4.2 subunit in histamine regulation of body temperature and its interaction with pERK1/2 downstream of the H3 receptor. We also reveal that this pathway provides a mechanism for selective modulation of body temperature at the beginning of the active phase of the circadian cycle.
The role of histamine H4 receptors as a potential targets in allergic rhinitis and asthma  [PDF]
Eva Hanuskova, Jana Plevkova
Open Journal of Molecular and Integrative Physiology (OJMIP) , 2013, DOI: 10.4236/ojmip.2013.31002
Abstract:

Histamine—the main product of mast cells plays critical role in the pathogenetic pathways of both allergic rhinitis and asthma. The novel concept of the unique airway diseases its only supported by the similarities within pathogenetic process. Antagonists of H1 and H2 receptors are quite effective in allergic rhinitis, but not effective enough in asthma. In an era of corticosteroids, leucotriene antagonists and Anti-IgE treatment, there is still a challenge to search for more effective, more acurate and more safe treatment option. Antagonists (inversive agonists) of histamine receptors H4 seems to be one of the promising targets in the allergic rhinitis and asthma treatment. The first H4 antagonist entered to clinics and the results from a proof-of-concept Phase II clinical study is expected to be disclosed soon. This review article summarizes current knowledge on H4R that have been collected in various studies sharing evidences about efficacy of H4R as a reasonable target for diseases with histamine involved pathogenetic pathways.

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