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Histamine Receptors (histamine + receptor)

Distribution by Scientific Domains

Life Sciences	54%
Medical Sciences	27%
Chemistry	18%

Selected Abstracts

Expression of histamine receptors and effect of histamine in the rat carotid body chemoafferent pathway

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2006
Nikolai Lazarov
Abstract Chemosensory information from peripheral arterial oxygen sensors in the carotid body is relayed by petrosal ganglion neurons to the respiratory networks in the medulla oblongata. Biogenic amines, including histamine, released from glomus (type I) cells of the carotid body are considered to be primary transmitters in hypoxic chemosensitivity. Immunocytochemistry at light-and electron-microscopical levels, and RT-PCR, revealed the expression of histamine receptors 1 and 3 as well as histidine decarboxylase in the rat carotid body glomus cells and petrosal ganglion neurons. Histamine receptors 1 and 3, but not histidine decarboxylase, were also observed in the ventrolateral, intermediate and commissural subnuclei of the nucleus tractus solitarii in the medulla oblongata. In order to examine the possible role of histamine in the afferent branch of the respiratory system, we applied histamine receptor 1 and 3 agonists to the carotid body, which caused a mildly increased phrenic nerve activity in a working heart,brainstem preparation. Moreover, microinjection of antagonists of histamine receptors 1 and 3 into the nucleus tractus solitarii caused significant changes in the inspiratory timing and the chemoreceptor response. Our data show that histamine acting via histamine receptors 1 and 3 plays an important neuromodulatory role in the afferent control of chemosensitivity. [source]

Synthesis of new 4,5,6,7-tetrahydro-3H -imidazo[4,5- c]pyridine derivatives

JOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 5 2003
Miguel F. Braña
The synthesis of new ligands for the H3 histamine receptor is described. These new compounds are spinacine derivatives obtained by alkylation or Michael reaction at C6 position. [source]

Effects of histamine receptor blockade on cardiovascular changes induced by 35 GHz radio frequency radiation heating

AUTONOMIC & AUTACOID PHARMACOLOGY, Issue 1 2004
J. R. Jauchem
Summary 1 The role of histamine in heat-induced cardiovascular changes is uncertain. The purpose of this study was to examine effects of histamine H-1- and H-2-antagonism on heart rate, mean arterial blood pressure (MAP), localized body temperature changes, survival times, and lethal body temperatures that occur during the exposure of anaesthetized rats to 35 GHz radio frequency radiation (RFR). 2 Forty-eight ketamine-anaesthetized Sprague,Dawley rats were exposed, in several different treatment groups (n = 8 in each), to 35 GHz RFR at a level that resulted in significant body heating and subsequent death. During irradiation, a continuous increase in heart rate and a biphasic response in blood pressure (initial increase followed by a decrease) were observed in all groups of animals. 3 An H-1-antagonist, diphenhydramine (1 mg kg,1 body wt) and an H-2-antagonist, cimetidine (5 mg kg,1), administered after sustained RFR exposure, failed to reverse the RFR-induced hypotension. High doses of the drugs (5 and 10 mg kg,1, respectively) also did not alter the response. Post-RFR survival time was significantly decreased in the high-dose drug-treated group, compared with vehicle-treated (0.9% NaCl, 50% ethanol and 50% D5W) controls. 4 In experiments in which the two drugs were administered prior to RFR exposure, MAP in animals receiving high-dose antihistamines was significantly depressed compared with that of vehicle-treated animals during the first 35 min of RFR exposure. Antihistamine pretreatment, however, did not alter the total RFR exposure time required for death to occur. 5 In summary, pharmacological blockade of H-1 and H-2 receptors is not beneficial in anaesthetized rats made hypotensive by RFR exposure. This indicates that activation of H-1 and H-2 receptors by histamine does not occur to any significant extent and does not mediate the hypotensive response developed in this model of hyperthermia. [source]

Expression of histamine receptors and effect of histamine in the rat carotid body chemoafferent pathway

Histamine H3 receptor-mediated impairment of contextual fear conditioning and in-vivo inhibition of cholinergic transmission in the rat basolateral amygdala

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2001
M. Beatrice Passani
Abstract We investigated the effects of agents acting at histamine receptors on both, spontaneous release of ACh from the basolateral amygdala (BLA) of freely moving rats, and fear conditioning. Extensive evidence suggests that the effects of histamine on cognition might be explained by the modulation of cholinergic systems. Using the microdialysis technique in freely moving rats, we demonstrated that perfusion of the BLA with histaminergic compounds modulates the spontaneous release of ACh. The addition of 100 mm KCl to the perfusion medium strongly stimulated ACh release, whereas, 0.5 µm tetrodotoxin (TTX) inhibited spontaneous ACh release by more than 50%. Histaminergic H3 antagonists (ciproxifan, clobenpropit and thioperamide), directly administered to the BLA, decreased ACh spontaneous release, an effect fully antagonized by the simultaneous perfusion of the BLA with cimetidine, an H2 antagonist. Local administration of cimetidine alone increased ACh spontaneous release slightly, but significantly. Conversely, the administration of H1 antagonists failed to alter ACh spontaneous release. Rats receiving intra-BLA, bilateral injections of the H3 antagonists at doses similar to those inhibiting ACh spontaneous release, immediately after contextual fear conditioning, showed memory consolidation impairment of contextual fear conditioning. Post-training, bilateral injections of 50 µg scopolamine also had an adverse effect on memory retention. These observations provide the first evidence that histamine receptors are involved in the modulation of cholinergic tone in the amygdala and in the consolidation of fear conditioning. [source]

Histamine induces neural stem cell proliferation and neuronal differentiation by activation of distinct histamine receptors

JOURNAL OF NEUROCHEMISTRY, Issue 2 2008
Anayansi Molina-Hernández
Abstract Histamine has neurotransmitter/neuromodulator functions in the adult brain, but its role during CNS development has been elusive. We studied histamine effects on proliferation, cell death and differentiation of neuroepithelial stem cells from rat cerebral cortex in vitro. RT-PCR and Western blot experiments showed that proliferating and differentiated cells express histamine H1, H2 and H3 receptors. Treatments with histamine concentrations (100 nM,1 mM) caused significant increases in cell numbers without affecting Nestin expression. Cell proliferation was evaluated by BrdU incorporation; histamine caused a significant increase dependent on H2 receptor activation. Apoptotic cell death during proliferation was significantly decreased at all histamine concentrations, and cell death was promoted in a concentration-dependent manner by histamine in differentiated cells. Immunocytochemistry studies showed that histamine increased 3-fold the number of neurons after differentiation, mainly by activation of H1 receptor, and also significantly decreased the glial (astrocytic) cell proportion, when compared to control conditions. In summary, histamine increases cell number during proliferative conditions, and has a neuronal-differentiating action on neural stem cells, suggesting that the elevated histamine concentration reported during development might play a role in cerebrocortical neurogenesis, by activation of H2 receptors to promote proliferation of neural precursors, and favoring neuronal fate by H1 -mediated stimulation. [source]

Novel Fused Pyrrole Heterocyclic Ring Systems as Structure Analogs of LE 300: Synthesis and Pharmacological Evaluation as Serotonin 5-HT2A, Dopamine and Histamine H1 Receptor Ligands

ARCHIV DER PHARMAZIE, Issue 2 2010
Sherif A. F. Rostom
Abstract LE 300 represents a structurally novel type of antagonists acting preferentially at the dopamine D1/D5 receptors and the serotonin 5-HT2A receptor. This compound consists of a ten-membered central azecine ring fused to an indole ring on one side and a benzene moiety on the other side. To estimate the importance of the indole and / or phenyl moieties in this highly active benz-indolo-azecine, both rings were removed and replaced with a 1H -pyrrole counterpart. Accordingly, some new analogs of LE 300 namely, pyrrolo[2,3- g]indolizine, pyrrolo[3,2- a]quinolizine rings and their corresponding dimethylpyrrolo[2,3- d]azonine, and dimethylpyrrolo[2,3- d]azecine were synthesized to be evaluated for their activity at the 5-HT2A and dopamine D1, D2L, D4, D5 receptors in relation to LE 300. In addition, their activity at the H1 -histamine receptors was also determined. The results suggested that the rigid pyrrolo[2,3- g]indolizine 7 and pyrrolo[3,2- a]quinolizine 8 analogs lacked biological activity in the adopted three bioassays. However, their corresponding flexible pyrrolo[2,3- d]azonine 11 and pyrrolo[2,3- d]azecine 12 derivatives revealed weak partial agonistic activity and weak antagonistic potency at the serotonin 5-HT2A and histamine H1 receptors, respectively. Meanwhile, they showed no affinity to any of the four utilized dopamine receptors. Variation in ring size did not contribute to a significant influence on the three tested bioactivities. Removal of the hydrophobic moiety (phenyl ring) and replacement of the indole moiety with a 1H -pyrrole counterpart led to a dramatic alteration in the profile of activity of such azecine-type compounds. [source]

Study on the antinociceptive action of Tyr-K-MIF-1, a peptide from the MIF family

AUTONOMIC & AUTACOID PHARMACOLOGY, Issue 2 2007
R. Zamfirova
Summary 1 Tyr-K-MIF-1 is a melanocyte inhibiting factor (MIF) neuropeptide, isolated from the brain. Opposite to other MIFs (Tyr-MIF-1, Tyr-W-MIF-1), it has a very low affinity for opiate , -receptors, but interacts with Tyr-MIF-1 specific binding sites. Tyr-MIF-1 and Tyr-W-MIF-1 evoke antinociception mainly by activating opioid receptors. We investigated the possible antinociceptive effect of Tyr-K-MIF-1 and the involvement of histaminergic system in its mechanism of action. 2 Tested on rats by paw-pressure test, Tyr-K-MIF-1 (0.5, 1 and 2 mg kg,1) was associated with short-lasting analgesia, which was abolished by naloxone (1 mg kg,1). 3 Injected intraperitoneally (i.p.) 15 min before Tyr-K-MIF-1, antagonists of H1 (diphenhydramine, 100 mg kg,1) or H2 (famotidine, 0.3 and 0.6 mg kg,1) histamine receptors diminished peptide antinociceptive effect. Simultaneous H1 - and H2 blockade, as well as pretreatment with 5 mg kg,1 dimaprit (H2 agonist) abolished Tyr-K-MIF-1-induced analgesia. Tyr-K-MIF-1-induced analgesia was also abolished by treatment with R-(,)-methylhistamine (10 mg kg,1, i.p.), an H3 histamine receptor agonist that acts to inhibit histamine release. 4 Our results together with data reported in the literature support the conclusion that activation of the histaminergic system is involved in the mechanism of Tyr-K-MIF-1-induced antinociception. [source]

Advances in histamine pharmacology reveal new drug targets

BRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2009
Paul L Chazot
This Themed Issue consists of three reviews and 11 original articles authored by internationally respected industrial and academic pharmacologists from across three continents. It derives from the highly successful symposium on ,The H3 and H4 histamine receptors: the antihistamines for the 21st century', which took place at EPHAR 2008 in Manchester University, and encompasses new roles, new compounds and exciting new therapeutic areas for histamine. [source]