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Coslovich T, Della Mora A, D'Angelo G, Ortolani F, Taccola G. Histamine H 3 Receptors Expressed in Ventral Horns Modulate Spinal Motor Output. Cell Mol Neurobiol 2020; 41:185-190. [PMID: 32211996 DOI: 10.1007/s10571-020-00831-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/16/2020] [Indexed: 11/29/2022]
Abstract
Motoneuron activity is modulated by histamine receptors. While H1 and H2 receptors have been widely explored, H3 histamine receptors (H3Rs) have not been sufficiently characterized. This paper targets the effects of the selective activation of H3Rs and their expression on the membranes of large ventral horn cells. The application of selective pharmacological agents to spinal cords isolated from neonatal rats was used to identify the presence of functional H3Rs on the membrane of physiologically identified lumbar motoneurons. Intra and extracellular recordings revealed that H3R agonist, α-methylhistamine, depolarized both single motoneurons and ventral roots, even in the presence of tetrodotoxin, an effect prevented by H3R antagonist, thioperamide. Finally, immunohistochemistry located the expression of H3Rs on a subpopulation of large cells in lamina IX. This study identifies H3Rs as a new exploitable pharmacological target against motor disturbances.
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Affiliation(s)
- Tamara Coslovich
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265, 34136, Trieste, TS, Italy.,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48, Udine, UD, Italy
| | - Alberto Della Mora
- Department of Experimental Clinical Medicine, University of Udine, Piazzale Kolbe 3, Udine, Italy
| | - Giuseppe D'Angelo
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265, 34136, Trieste, TS, Italy.,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48, Udine, UD, Italy
| | - Fulvia Ortolani
- Department of Experimental Clinical Medicine, University of Udine, Piazzale Kolbe 3, Udine, Italy
| | - Giuliano Taccola
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265, 34136, Trieste, TS, Italy. .,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48, Udine, UD, Italy.
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Matsuoka I, Ito J, Takahashi H, Sasa M, Takaori S. Experimental Vestibular Pharmacology: A Minireview with Special Reference to Neuroactive Substances and Antivertigo Drugs. Acta Otolaryngol 2018. [DOI: 10.1080/00016489.1985.12005655] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Izuru Matsuoka
- Department of Otorhinolaryngology and Kyoto University, Kyoto, Japan
| | - Juichi Ito
- Department of Otorhinolaryngology and Kyoto University, Kyoto, Japan
| | - Haruo Takahashi
- Department of Otorhinolaryngology and Kyoto University, Kyoto, Japan
| | - Masashi Sasa
- Department of Pharmacology, Faculty of Medicine, Kyoto University, Kyoto, Japan
| | - Shuji Takaori
- Department of Pharmacology, Faculty of Medicine, Kyoto University, Kyoto, Japan
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Coslovich T, Brumley MR, D'Angelo G, Della Mora A, Swann HE, Ortolani F, Taccola G. Histamine modulates spinal motoneurons and locomotor circuits. J Neurosci Res 2017; 96:889-900. [PMID: 29114923 DOI: 10.1002/jnr.24195] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 10/01/2017] [Accepted: 10/16/2017] [Indexed: 12/20/2022]
Abstract
Spinal motoneurons and locomotor networks are regulated by monoamines, among which, the contribution of histamine has yet to be fully addressed. The present study investigates histaminergic regulation of spinal activity, combining intra- and extracellular electrophysiological recordings from neonatal rat spinal cord in vitro preparations. Histamine dose-dependently and reversibly generated motoneuron depolarization and action potential firing. Histamine (20 µM) halved the area of dorsal root reflexes and always depolarized motoneurons. The majority of cells showed a transitory repolarization, while 37% showed a sustained depolarization maintained with intense firing. Extracellularly, histamine depolarized ventral roots (VRs), regardless of blockage of ionotropic glutamate receptors. Initial, transient glutamate-mediated bursting was synchronous among VRs, with some bouts of locomotor activity in a subgroup of preparations. After washout, the amplitude of spontaneous tonic discharges increased. No desensitization or tachyphylaxis appeared after long perfusion or serial applications of histamine. On the other hand, histamine induced single motoneuron and VR depolarization, even in the presence of tetrodotoxin (TTX). During chemically induced fictive locomotion (FL), histamine depolarized VRs. Histamine dose-dependently increased rhythm periodicity and reduced cycle amplitude until near suppression. This study demonstrates that histamine induces direct motoneuron membrane depolarization and modulation of locomotor output, indicating new potential targets for locomotor neurorehabilitation.
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Affiliation(s)
- Tamara Coslovich
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265 Trieste, (TS), Italy.,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48 Udine (UD), Italy
| | | | - Giuseppe D'Angelo
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265 Trieste, (TS), Italy.,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48 Udine (UD), Italy
| | - Alberto Della Mora
- Department of Experimental Clinical Medicine, University of Udine, Piazzale Kolbe 3 Udine, Italy
| | | | - Fulvia Ortolani
- Department of Experimental Clinical Medicine, University of Udine, Piazzale Kolbe 3 Udine, Italy
| | - Giuliano Taccola
- Neuroscience Department, International School for Advanced Studies (SISSA), via Bonomea 265 Trieste, (TS), Italy.,SPINAL (Spinal Person Injury Neurorehabilitation Applied Laboratory), Istituto di Medicina Fisica e Riabilitazione (IMFR), via Gervasutta 48 Udine (UD), Italy
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Li B, Zhu JN, Wang JJ. Histaminergic afferent system in the cerebellum: structure and function. CEREBELLUM & ATAXIAS 2014; 1:5. [PMID: 26331029 PMCID: PMC4549136 DOI: 10.1186/2053-8871-1-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 03/14/2014] [Indexed: 12/16/2022]
Abstract
Histaminergic afferent system of the cerebellum, having been considered as an essential component of the direct hypothalamocerebellar circuits, originates from the tuberomammillary nucleus in the hypothalamus. Unlike the mossy fibers and climbing fibers, the histaminergic afferent fibers, a third type of cerebellar afferents, extend fine varicose fibers throughout the cerebellar cortex and nuclei. Histamine receptors, belonging to the family of G protein-coupled receptors, are widely present in the cerebellum. Through these histamine receptors, histamine directly excites Purkinje cells and granule cells in the cerebellar cortex, as well as the cerebellar nuclear neurons. Therefore, the histaminergic afferents parallelly modulate these dominant components in the cerebellar circuitry and consequently influence the final output of the cerebellum. In this way, the histaminergic afferent system actively participates in the cerebellum-mediated motor balance and coordination and nonsomatic functions. Accordingly, histaminergic reagents may become potential drugs for clinical treatment of cerebellar ataxia and other cerebellar disease. On the other hand, considering the hypothalamus is a high regulatory center for autonomic and visceral activities, the hypothalamocerebellar histaminergic fibers/projections, bridging the nonsomatic center to somatic structure, may play a critical role in the somatic-nonsomatic integration.
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Affiliation(s)
- Bin Li
- Department of Biological Science and Technology and State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Mailbox 426, 22 Hankou Road, Nanjing, 210093 China
| | - Jing-Ning Zhu
- Department of Biological Science and Technology and State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Mailbox 426, 22 Hankou Road, Nanjing, 210093 China
| | - Jian-Jun Wang
- Department of Biological Science and Technology and State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Mailbox 426, 22 Hankou Road, Nanjing, 210093 China
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Sim YB, Park SH, Kim SS, Kim CH, Kim SJ, Lim SM, Jung JS, Ryu OH, Choi MG, Suh HW. The modulatory role of spinally located histamine receptors in the regulation of the blood glucose level in d-glucose-fed mice. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2014; 18:41-6. [PMID: 24634595 PMCID: PMC3951822 DOI: 10.4196/kjpp.2014.18.1.41] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Revised: 12/06/2013] [Accepted: 12/27/2013] [Indexed: 11/21/2022]
Abstract
The possible roles of spinal histamine receptors in the regulation of the blood glucose level were studied in ICR mice. Mice were intrathecally (i.t.) treated with histamine 1 (H1) receptor agonist (2-pyridylethylamine) or antagonist (cetirizine), histamine 2 (H2) receptor agonist (dimaprit) or antagonist (ranitidine), histamine 3 (H3) receptor agonist (α-methylhistamine) or antagonist (carcinine) and histamine 4 (H4) receptor agonist (VUF 8430) or antagonist (JNJ 7777120), and the blood glucose level was measured at 30, 60 and 120 min after i.t. administration. The i.t. injection with α-methylhistamine, but not carcinine slightly caused an elevation of the blood glucose level. In addition, histamine H1, H2, and H4 receptor agonists and antagonists did not affect the blood glucose level. In D-glucose-fed model, i.t. pretreatment with cetirizine enhanced the blood glucose level, whereas 2-pyridylethylamine did not affect. The i.t. pretreatment with dimaprit, but not ranitidine, enhanced the blood glucose level in D-glucose-fed model. In addition, α-methylhistamine, but not carcinine, slightly but significantly enhanced the blood glucose level D-glucose-fed model. Finally, i.t. pretreatment with JNJ 7777120, but not VUF 8430, slightly but significantly increased the blood glucose level. Although histamine receptors themselves located at the spinal cord do not exert any effect on the regulation of the blood glucose level, our results suggest that the activation of spinal histamine H2 receptors and the blockade of spinal histamine H1 or H3 receptors may play modulatory roles for up-regulation and down-regulation, respectively, of the blood glucose level in D-glucose fed model.
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Affiliation(s)
- Yun-Beom Sim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
| | - Soo-Hyun Park
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
| | - Sung-Su Kim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
| | - Chea-Ha Kim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
| | - Su-Jin Kim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
| | - Su-Min Lim
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
| | - Jun-Sub Jung
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
| | - Ohk-Hyun Ryu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
| | - Moon-Gi Choi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
| | - Hong-Won Suh
- Department of Pharmacology, Institute of Natural Medicine, College of Medicine, Hallym University, Chuncheon 200-702, Korea
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Cevikbas F, Steinhoff M, Ikoma A. Role of spinal neurotransmitter receptors in itch: new insights into therapies and drug development. CNS Neurosci Ther 2011; 17:742-9. [PMID: 20950328 PMCID: PMC6493876 DOI: 10.1111/j.1755-5949.2010.00201.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Targets for antipruritic therapies are now expanding from the skin to the central nervous system. Recent studies demonstrate that various neuronal receptors in the spinal cord are involved in pruritus. The spinal opioid receptor is one of the best-known examples. Spinal administration of morphine is frequently accompanied by segmental pruritus. In addition to μ-opioid receptor antagonists, κ-opioid receptor agonists have recently come into usage as novel antipruritic drugs, and are expected to suppress certain subtypes of itch such as hemodialysis- and cholestasis-associated itch that are difficult to treat with antihistamines. The gastrin-releasing peptide receptor in the superficial dorsal horn of the spinal cord has also received recent attention as a novel pathway of itch-selective neural transmission. The NMDA glutamate receptor appears to be another potential target for the treatment of itch, especially in terms of central sensitization. The development of NMDA receptor antagonists with less undesirable side effects on the central nervous system might be beneficial for antipruritic therapies. Drugs suppressing presynaptic glutamate-release such as gabapentin and pregabalin also reportedly inhibit certain subtypes of itch such as brachioradial pruritus. Spinal receptors of other neuromediators such as bradykinin, substance P, serotonin, and histamine may also be potential targets for antipruritic therapies, given that most of these molecules interfere not only with pain, but also with itch transmission or regulation. Thus, the identification of itch-specific receptors and understanding itch-related circuits in the spinal cord may be innovative strategies for the development of novel antipruritic drugs.
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MESH Headings
- Animals
- Drug Design
- Gastrin-Secreting Cells/drug effects
- Gastrin-Secreting Cells/physiology
- Humans
- Neurotransmitter Agents/physiology
- Pruritus/drug therapy
- Pruritus/physiopathology
- Receptors, Bradykinin/drug effects
- Receptors, Bradykinin/physiology
- Receptors, Glutamate/drug effects
- Receptors, Glutamate/physiology
- Receptors, Histamine/drug effects
- Receptors, Histamine/physiology
- Receptors, Neurokinin-1/drug effects
- Receptors, Neurokinin-1/physiology
- Receptors, Opioid/drug effects
- Receptors, Opioid/physiology
- Receptors, Serotonin/drug effects
- Receptors, Serotonin/physiology
- Spinal Cord/physiology
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Affiliation(s)
- Ferda Cevikbas
- Departments of Dermatology and Surgery, University of California, San Francisco, USA
| | - Martin Steinhoff
- Departments of Dermatology and Surgery, University of California, San Francisco, USA
| | - Akihiko Ikoma
- Departments of Dermatology and Surgery, University of California, San Francisco, USA
- Department of Dermatology, Kyoto University, Japan
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Wu GY, Han XH, Zhuang QX, Zhang J, Yung WH, Chan YS, Zhu JN, Wang JJ. Excitatory effect of histamine on rat spinal motoneurons by activation of both H1 and H2 receptors in vitro. J Neurosci Res 2011; 90:132-42. [DOI: 10.1002/jnr.22730] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 05/24/2011] [Accepted: 05/31/2011] [Indexed: 11/06/2022]
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Abstract
In this article, we review the recent developments in the field of histamine research. Besides the description of pharmacological tools for the H1, H2 and H3 receptor, specific attention is paid to both the molecular aspects of the receptor proteins, including the recent cloning of the receptor genes, and their respective signal transduction mechanisms.
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MESH Headings
- Amino Acid Sequence
- Animals
- Cloning, Molecular
- Gene Expression Regulation/genetics
- Histamine Agonists/pharmacology
- Histamine Antagonists/pharmacology
- Humans
- Ligands
- Molecular Sequence Data
- Receptors, Histamine/chemistry
- Receptors, Histamine/classification
- Receptors, Histamine/genetics
- Receptors, Histamine/metabolism
- Receptors, Histamine H1/chemistry
- Receptors, Histamine H1/genetics
- Receptors, Histamine H1/metabolism
- Receptors, Histamine H2/chemistry
- Receptors, Histamine H2/genetics
- Receptors, Histamine H2/metabolism
- Receptors, Histamine H3/chemistry
- Receptors, Histamine H3/genetics
- Receptors, Histamine H3/metabolism
- Signal Transduction/genetics
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Affiliation(s)
- R Leurs
- Leiden/Amsterdam Center for Drug Research, Department of Pharmacochemistry, Vrije, Universiteit, The Netherlands
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Nakai T, Kitamura N, Hashimoto T, Kajimoto Y, Nishino N, Mita T, Tanaka C. Decreased histamine H1 receptors in the frontal cortex of brains from patients with chronic schizophrenia. Biol Psychiatry 1991; 30:349-56. [PMID: 1912125 DOI: 10.1016/0006-3223(91)90290-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Involvement of histamine H1 receptor in the brains of schizophrenic patients was investigated using 3H-mepyramine as a ligand. The specific 3H-mepyramine binding in the frontal cortex was saturable with the dissociation constant (Kd) of about 0.6 nM and the maximum number of binding sites (Bmax) of 64 fmol/mg protein. Specific H1 antagonists, mepyramine (Ki = 1.4 nM), promethazine (Ki = 1.4 nM), diphenylpyraline (Ki = 4.1 nM), triprolidine (Ki = 5.3 nM), diphenylhydramine (Ki = 35 nM), but not the specific H2 antagonist, cimetidine (Ki greater than 10(5) nM), strongly inhibited the 3H-mepyramine binding. Regional distribution of the specific 3H-mepyramine binding was in the order of: frontal cortex greater than hippocampus greater than cerebellum greater than hypothalamus greater than thalamus, putamen, and pallidum. The specific 3H-mepyramine binding in schizophrenic brains was reduced by 56% in the frontal cortex. Representative Scatchard analyses of the specific 3H-mepyramine binding revealed changes resulting from a decrease in receptor density but not in receptor affinity. Down-regulation of the histamine H1 receptor in the frontal cortex may be involved in the pathophysiology of schizophrenia.
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Affiliation(s)
- T Nakai
- Department of Pharmacology, Kobe University School of Medicine, Japan
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Abstract
The actions of histamine and histamine antagonists on afferent nerve activity were investigated in the lateral line of Xenopus laevis. Histamine (0.002-2.0 mM) had no effect on spontaneous activity or excitatory responses to water motion. In contrast, pyrilamine, an H1 receptor antagonist, suppressed spontaneous activity beginning at 0.01-0.05 mM. Below 0.3 mM the suppression was often preceded by a small excitatory response and responses to high (24-30 dB re threshold), but not low (0-18 dB) levels of water motion were selectively suppressed. Higher concentrations (0.3-2.0 mM) abolished spontaneous activity and suppressed responses at all levels of water motion. Cimetidine, an H2 receptor antagonist, had similar actions but was one-tenth as potent as pyrilamine. Tetrodotoxin (0.001-0.1 microM), which blocks voltage-sensitive Na+ channels, mimicked the suppressive effects of the histamine antagonists. Histamine (2.0 mM) failed to block the actions of pyrilamine (0.1 mM) indicating its effects are mediated through a mechanism other than histamine receptors. In addition, pyrilamine (0.05-0.1 mM) non-selectively suppressed excitation to exogenously applied L-glutamate (1.0-2.0 mM), L-aspartate (1.0-2.0 mM), kainate (0.005-0.01 mM), and quisqualate (0.002-0.005 mM) and altered responses to N-methyl-D-aspartate (0.5-1.0 mM). The results are inconsistent with histamine being a transmitter in the Xenopus lateral line and reveal that the actions of histamine antagonists are nonspecific, possibly due, in part, to blockade of voltage-sensitive Na+ channels.
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Affiliation(s)
- S C Bledsoe
- Kresge Hearing Research Institute, University of Michigan Medical School, Ann Arbor 48109-0506
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Hill SJ. Histamine receptors in the mammalian central nervous system: biochemical studies. PROGRESS IN MEDICINAL CHEMISTRY 1987; 24:29-84. [PMID: 2849144 DOI: 10.1016/s0079-6468(08)70419-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Yaksh TL, Dirksen R, Harty GJ. Antinociceptive effects of intrathecally injected cholinomimetic drugs in the rat and cat. Eur J Pharmacol 1985; 117:81-8. [PMID: 3841316 DOI: 10.1016/0014-2999(85)90474-1] [Citation(s) in RCA: 188] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Rats chronically implanted with intrathecal catheters displayed a dose-dependent increase in the hot-plate, tail-flick response latencies, and decreased the magnitude of the writhing response following the injection of certain cholinomimetics into the subarachnoid space through the indwelling catheter. The structure-activity relationship for these agents is oxotremorine greater than carbachol greater than acetylcholine + physostigmine much much greater than acetylcholine = nicotine-HCl = 0. Atropine, but not naloxone, strychnine, picrotoxin, curare or methysergide and phentolamine, reversed the antinociceptive effect. This suggests the involvement of muscarinic cholinergic mechanisms. Experiments with intrathecal injection of carbachol into the spinal subarachnoid space of cats fitted with intrathecal catheters also revealed a potent antinociceptive effect which was completely antagonized by atropine. The effect was somatotopically limited with the skin surfaces innervated by cord segments nearest the catheter tip showing the most significant effect with the shortest latency of onset. This observation, together with the absence of changes in general reflex motor function or postural control further indicated a selective spinal effectiveness of muscarinic agonists after low dose intrathecal administration.
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Hösli E, Hösli L. Autoradiographic localization of binding sites for [3H]histamine and H1- and H2-antagonists on cultured neurones and glial cells. Neuroscience 1984; 13:863-70. [PMID: 6527781 DOI: 10.1016/0306-4522(84)90101-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
By means of autoradiography we have studied the cellular localization of binding of [3H]histamine and H1- and H2-antagonists in explant cultures of rat cerebellum, brain stem and spinal cord. In brain stem and spinal cord cultures, a relatively great number of neurones revealed binding sites for [3H]histamine and to a lesser extent also for the H1-antagonist [3H]pyrilamine and for the H2-antagonist [3H]tiotidine. In contrast, only a small number of labelled neurones was found in cerebellar cultures. The intensity of labelling was usually much stronger for [3H]histamine than for its antagonists, suggesting that binding sites for histamine might reflect both H1- and H2-receptors. Glial cells also showed binding sites for [3H]histamine and the H1- and H2-antagonists, the number of labelled astrocytes by these radioligands was, however, smaller than that observed with [3H]noradrenaline and alpha- and beta-adrenergic antagonists. It is suggested that in addition to alpha- and beta-adrenoceptors, glial cells also possess receptors for histamine.
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Kanba S, Richelson E. Antidepressants are weak competitive antagonists of histamine H2 receptors in dissociated brain tissue. Eur J Pharmacol 1983; 94:313-8. [PMID: 6140176 DOI: 10.1016/0014-2999(83)90420-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Guinea pig hippocampus dissociated by mechanical means into uniform clumps of cells (approximately 100 micron in diameter) contains histamine receptors (H1 and H2) which mediate the formation of cyclic AMP. In this preparation, antidepressants are very potent antagonists of histamine H1 receptors but are weak antagonists of histamine H2 receptors. The latter result is contrary to data derived by others using homogenates of the guinea pig hippocampus and seems to dispel the idea that antidepressants derive their efficacy by blocking histamine H2 receptors in brain.
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