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Why Monoamine Oxidase B Preferably Metabolizes N-Methylhistamine over Histamine: Evidence from the Multiscale Simulation of the Rate-Limiting Step. Int J Mol Sci 2022; 23:ijms23031910. [PMID: 35163835 PMCID: PMC8836602 DOI: 10.3390/ijms23031910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 02/04/2022] [Accepted: 02/05/2022] [Indexed: 11/18/2022] Open
Abstract
Histamine levels in the human brain are controlled by rather peculiar metabolic pathways. In the first step, histamine is enzymatically methylated at its imidazole Nτ atom, and the produced N-methylhistamine undergoes an oxidative deamination catalyzed by monoamine oxidase B (MAO-B), as is common with other monoaminergic neurotransmitters and neuromodulators of the central nervous system. The fact that histamine requires such a conversion prior to oxidative deamination is intriguing since MAO-B is known to be relatively promiscuous towards monoaminergic substrates; its in-vitro oxidation of N-methylhistamine is about 10 times faster than that for histamine, yet this rather subtle difference appears to be governing the decomposition pathway. This work clarifies the MAO-B selectivity toward histamine and N-methylhistamine by multiscale simulations of the rate-limiting hydride abstraction step for both compounds in the gas phase, in aqueous solution, and in the enzyme, using the established empirical valence bond methodology, assisted by gas-phase density functional theory (DFT) calculations. The computed barriers are in very good agreement with experimental kinetic data, especially for relative trends among systems, thereby reproducing the observed MAO-B selectivity. Simulations clearly demonstrate that solvation effects govern the reactivity, both in aqueous solution as well as in the enzyme although with an opposing effect on the free energy barrier. In the aqueous solution, the transition-state structure involving histamine is better solvated than its methylated analog, leading to a lower barrier for histamine oxidation. In the enzyme, the higher hydrophobicity of N-methylhistamine results in a decreased number of water molecules at the active side, leading to decreased dielectric shielding of the preorganized catalytic electrostatic environment provided by the enzyme. This renders the catalytic environment more efficient for N-methylhistamine, giving rise to a lower barrier relative to histamine. In addition, the transition state involving N-methylhistamine appears to be stabilized by the surrounding nonpolar residues to a larger extent than with unsubstituted histamine, contributing to a lower barrier with the former.
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Villar-Briones A, Aird SD. Organic and Peptidyl Constituents of Snake Venoms: The Picture Is Vastly More Complex Than We Imagined. Toxins (Basel) 2018; 10:E392. [PMID: 30261630 PMCID: PMC6215107 DOI: 10.3390/toxins10100392] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 09/18/2018] [Accepted: 09/20/2018] [Indexed: 12/24/2022] Open
Abstract
Small metabolites and peptides in 17 snake venoms (Elapidae, Viperinae, and Crotalinae), were quantified using liquid chromatography-mass spectrometry. Each venom contains >900 metabolites and peptides. Many small organic compounds are present at levels that are probably significant in prey envenomation, given that their known pharmacologies are consistent with snake envenomation strategies. Metabolites included purine nucleosides and their bases, neurotransmitters, neuromodulators, guanidino compounds, carboxylic acids, amines, mono- and disaccharides, and amino acids. Peptides of 2⁻15 amino acids are also present in significant quantities, particularly in crotaline and viperine venoms. Some constituents are specific to individual taxa, while others are broadly distributed. Some of the latter appear to support high anabolic activity in the gland, rather than having toxic functions. Overall, the most abundant organic metabolite was citric acid, owing to its predominance in viperine and crotaline venoms, where it chelates divalent cations to prevent venom degradation by venom metalloproteases and damage to glandular tissue by phospholipases. However, in terms of their concentrations in individual venoms, adenosine, adenine, were most abundant, owing to their high titers in Dendroaspis polylepis venom, although hypoxanthine, guanosine, inosine, and guanine all numbered among the 50 most abundant organic constituents. A purine not previously reported in venoms, ethyl adenosine carboxylate, was discovered in D. polylepis venom, where it probably contributes to the profound hypotension caused by this venom. Acetylcholine was present in significant quantities only in this highly excitotoxic venom, while 4-guanidinobutyric acid and 5-guanidino-2-oxopentanoic acid were present in all venoms.
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Affiliation(s)
- Alejandro Villar-Briones
- Division of Research Support, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan.
| | - Steven D Aird
- Division of Faculty Affairs and Ecology and Evolution Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan.
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Prell GD, Martinelli GP, Holstein GR, Matulić-Adamić J, Watanabe KA, Chan SLF, Morgan NG, Haxhiu MA, Ernsberger P. Imidazoleacetic acid-ribotide: an endogenous ligand that stimulates imidazol(in)e receptors. Proc Natl Acad Sci U S A 2004; 101:13677-82. [PMID: 15365189 PMCID: PMC518812 DOI: 10.1073/pnas.0404846101] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2004] [Indexed: 11/18/2022] Open
Abstract
We identified the previously unknown structures of ribosylated imidazoleacetic acids in rat, bovine, and human tissues to be imidazole-4-acetic acid-ribotide (IAA-RP) and its metabolite, imidazole-4-acetic acid-riboside. We also found that IAA-RP has physicochemical properties similar to those of an unidentified substance(s) extracted from mammalian tissues that interacts with imidazol(in)e receptors (I-Rs). ["Imidazoline," by consensus (International Union of Pharmacology), includes imidazole, imidazoline, and related compounds. We demonstrate that the imidazole IAA-RP acts at I-Rs, and because few (if any) imidazolines exist in vivo, we have adopted the term "imidazol(in)e-Rs."] The latter regulate multiple functions in the CNS and periphery. We now show that IAA-RP (i) is present in brain and tissue extracts that exhibit I-R activity; (ii) is present in neurons of brainstem areas, including the rostroventrolateral medulla, a region where drugs active at I-Rs are known to modulate blood pressure; (iii) is present within synaptosome-enriched fractions of brain where its release is Ca(2+)-dependent, consistent with transmitter function; (iv) produces I-R-linked effects in vitro (e.g., arachidonic acid and insulin release) that are blocked by relevant antagonists; and (v) produces hypertension when microinjected into the rostroventrolateral medulla. Our data also suggest that IAA-RP may interact with a novel imidazol(in)e-like receptor at this site. We propose that IAA-RP is a neuroregulator acting via I-Rs.
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Affiliation(s)
- George D Prell
- Department of Pharmacology and Biological Chemistry, Mount Sinai School of Medicine, New York, NY 10029, USA.
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Abstract
1. Imidazole 4-acetic acid (IMA) is a naturally occurring metabolite in brain, although it is unclear what biochemical pathways are involved in its biosynthesis and breakdown. Some evidence, however, suggests that IMA is an oxidation product of histamine. 2. The compound has pronounced neuropharmacological properties, many of which are consistent with an activation of GABA(A) receptors. Indeed, IMA is able to displace [3H]GABA from GABA(A) sites in a potent manner. 3. IMA displays definite partial agonist characteristics as an enhancer of benzodiazepine binding to the GABA(A) receptor complex in membrane preparations. In addition, it has an affinity for GABA(C) receptors, where it seems to act as an antagonist, and perhaps as a weak partial agonist. A third recognition site for IMA in brain is the I1-imidazoline receptor. 4. Parenteral administration to experimental animals leads to a sleep-like state which can often be accompanied by seizures. In addition, central application of IMA has been associated with a dose-related reduction in arterial pressure and sympathetic nervous discharge. 5. No specific receptor site or uptake system for IMA has yet been discovered, adding uncertainty to its role in central nervous system function. Yet the possibility cannot be overlooked that IMA plays a role in regulating blood pressure.
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Affiliation(s)
- G Tunnicliff
- Laboratory of Neurochemistry, Indiana University School of Medicine, Evansville 47712, USA.
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Lecklin A, Tuomisto L. Fluid balance in rats of three different strains after inhibition of histamine catabolism. Physiol Behav 1995; 58:861-7. [PMID: 8577881 DOI: 10.1016/0031-9384(95)00131-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effect of metoprine, an inhibitor of histamine (HA) catabolism, on fluid balance was studied in Wistar (W) and Long-Evans (LE) rats. AVP deficient Brattleboro (BB) rats were used to evaluate which phenomena were AVP-related. W and LE rats were quite different: LE rats were "dry" rats, they drank less, had higher plasma AVP, smaller urine volume and excreted more AVP, and responded less to salt loading and water deprivation. Furthermore, LE and W rats responded differently to metoprine. When water was provided as drinking fluid, metoprine increased water intake and urine flow in W rats, but these changes were not significant in LE rats. In contrast, when the rats drank saline, urine output and saline consumption were similarly decreased in LE and W rats. Although no metoprine-induced changes in plasma AVP were observed, urinary excretion of AVP per 24 h was reduced in metoprine treated rats. Inhibition of HA catabolism by metoprine caused only minor changes in fluid balance of AVP deficient BB rats. The results show that significant differences in fluid balance can exist between rat strains and that increased availability of HA after IP given metoprine strongly affects body fluids in normal rats, especially those of the W strain. The results provide further support to the involvement of HA in the regulation of fluid balance, but to obtain a more complete picture, other factors, such as atrial natriuretic peptide, should be studied.
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Affiliation(s)
- A Lecklin
- Department of Pharmacology and Toxicology, University of Kuopio, Finland
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Gianelli M, Cantello R, Civardi C, Naldi P, Bettucci D, Schiavella MP, Mutani R. Idiopathic generalized epilepsy: magnetic stimulation of motor cortex time-locked and unlocked to 3-Hz spike-and-wave discharges. Epilepsia 1994; 35:53-60. [PMID: 8112258 DOI: 10.1111/j.1528-1157.1994.tb02912.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In 20 patients with idiopathic generalized epilepsy who showed typical 3-Hz spike-and-wave (SW) EEG complexes, we studied the corticospinal motor output with a transcranial electromagnetic stimulator. First we measured the corticospinal discharge threshold for both hemispheres in the patient group and compared it with that of 10 age- and sex-matched volunteers. Threshold was significantly higher in the patient group, regardless of whether subjects were treated with antiepileptic drugs (AEDs). In 4 patients with very frequent SW paroxysms, we were able to study motor evoked potential (MEP) changes time-locked to epileptic EEG transients. The EEG signal was recorded bipolarly (C3-P3, C4-P4) by scalp needle-electrodes. For a given stimulus intensity, we collected and measured MEPs occurring during the spike or the wave portion of the SW complexes. Data were compared with those of MEPs obtained time-locked to normal EEG segments. MEP size was significantly decreased when the cortical stimulus was time-locked to the wave component, and was decreased or unchanged when the stimulus was time-locked to the spike. Magnetic stimulation never produced remarkable side effects.
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Affiliation(s)
- M Gianelli
- University Department of Neurology, Ospedale Maggiore, Novara, Italy
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7
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Sturman G, Freeman P. Histaminergic modulation and chemically-induced seizures in mice. ACTA ACUST UNITED AC 1992. [DOI: 10.1007/bf01997373] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Gammahydroxybutyrate is a naturally occurring metabolite of many mammalian tissues. Although its administration produces a wide range of pharmacological effects, its normal function has never been clearly defined. GHB can induce NREM and REM sleep, anaesthesia, hypothermia, and a trance-like state which has been considered a model for petit mal epilepsy. It markedly increases brain dopamine levels. It has been touted as a central neurotransmitter or neuromodulator, and high affinity brain receptors, as well as central mechanisms for its synthesis, uptake and release have been demonstrated in support of this. But GHB is also found in many peripheral tissues and in some of these in higher concentrations than in the brain. No explanation has been offered for its presence in these tissues. A number of studies indicate that GHB can reduce energy substrate consumption in both brain and peripheral tissues, and that it can protect these tissues from the damaging effects of anoxia or excessive metabolic demand. Indeed there is some evidence to suggest that endogenous GHB levels rise under these circumstances. GHB appears to act through the endogenous opioid system, since in the brain, at least, GHB raises dynorphin levels and its metabolic and pharmacological effects can be blocked by naloxone. These, and other observations detailed in this review, suggest that GHB may function naturally in the induction and maintenance of physiological states, like sleep and hibernation, in which energy utilization is depressed. GHB may also function naturally as an endogenous protective agent when tissue energy supplies are limited.
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Affiliation(s)
- M Mamelak
- Department of Psychiatry, Sunnybrook Medical Centre, University of Toronto, Ontario, Canada
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KROGSGAARD-LARSEN POVL, HJEDS HANS, FALCH ERIK, JØRGENSEN FLEMMINGS, NIELSEN LONE. Recent Advances in GABA Agonists, Antagonists and Uptake Inhibitors: Structure–Activity Relationships and Therapeutic Potential. ADVANCES IN DRUG RESEARCH 1988. [DOI: 10.1016/b978-0-12-013317-8.50009-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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10
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Ferrari F, Baggio G, Mangiafico V. Effects of imidazole and some imidazole-derivatives on lisuride-induced mounting and aggressiveness. Psychopharmacology (Berl) 1987; 93:19-24. [PMID: 3114811 DOI: 10.1007/bf02439581] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Adult male rats were treated intraperitoneally (IP) with imidazole (IMID), distilled water or saline prior to administration of lisuride either IP or intracerebroventricularly (ICV) at doses too low by themselves to elicit the behavioural signs of mounting and aggressiveness, typically induced by higher doses of this drug. Pretreatment with distilled water or saline, or the procedure of injection alone, stimulated mounting in some of the animals. At a certain range of doses IMID induced a marked increase in both mounting and aggressive posturing in the same animals, while at higher doses mounting ceased, violent aggressive behaviour appeared and some of the rats died. Seven IMID derivatives were used on the lisuride-test: N-methylimidazole, 2-methylimidazole, 4-methylimidazole, N-acetylimidazole, 4-imidaaoleacetic acid, clonidine and cimetidine. Only 4-imidazoleacetic acid was completely ineffective with respect to controls. All the other drugs enhanced aggressive behaviour to varying degrees but proved to be less potent than IMID in inducing mounting, and clonidine reduced mounting at all the doses tested.
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Abstract
The clinical and biochemical disturbances of a patient with seasonal hypomania and cold urticaria are described and discussed with reference to histamine metabolism in mental disorder.
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Marescaux C, Micheletti G, Vergnes M, Rumbach L, Warter JM. Diazepam antagonizes GABAmimetics in rats with spontaneous petit mal-like epilepsy. Eur J Pharmacol 1985; 113:19-24. [PMID: 2995058 DOI: 10.1016/0014-2999(85)90338-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Wistar rats in our laboratory breeding colony spontaneously present petit mal-like, non-convulsive, epileptic seizures. In these rats, as in other animal petit mal models, GABAmimetics, agonists of GABA-A receptors such as 4, 5, 6, 7 tetrahydroisooxazolo (5,4-c) pyridin-3-ol (THIP), or inhibitors of GABA catabolism such as gamma-vinyl GABA (GVG) or L-cycloserine (CYC), aggravated the seizures. Diazepam not only abolished the spontaneous seizures but also completely blocked the effects of the GABAmimetics, totally suppressing seizures in rats given THIP, GVG or CYC. These findings show that the mode of action of benzodiazepines is not comparable to a non-specific potentiation of GABA transmission, and suggest that the anti-absence effects of the benzodiazepines could depend on interactions with neurotransmitter systems other than GABA.
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Vergnes M, Marescaux C, Micheletti G, Rumbach L, Warter JM. Blockade of "antiabsence" activity of sodium valproate by THIP in rats with petit mal-like seizures. Comparison with ethosuximide. J Neural Transm (Vienna) 1985; 63:133-41. [PMID: 3930659 DOI: 10.1007/bf01252613] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Wistar rats from our laboratory spontaneously present frequent epileptic seizures whose clinical semeiology, EEG signs and pharmacological reactivity resemble absence seizures in humans. In these rats, GABAmimetics such as THIP enhance the duration of seizures in a dose-dependent fashion. In contrast to the action of these drugs, valproate sodium (VPA), which potentiates GABAergic transmission, abolishes the seizures. VPA injected in association with THIP completely loses its therapeutic effects; moreover, VPA potentiates the aggravating effects of THIP. Ethosuximide which does not interact with GABA, was still effective when given in association with THIP. These findings raise questions as to 1. the role of GABAergic neurotransmission in the occurrence of spontaneous petit-mal-like seizures in the rat, and 2. the mode of action of antiepileptics against these seizures.
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Krogsgaard-Larsen P, Falch E, Hjeds H. Heterocyclic analogues of GABA: chemistry, molecular pharmacology and therapeutic aspects. PROGRESS IN MEDICINAL CHEMISTRY 1985; 22:67-120. [PMID: 3014606 DOI: 10.1016/s0079-6468(08)70229-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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15
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Mohan Kumar V, Datta S, Chhina GS, Gandhi N, Singh B. Sleep-awake responses elicited from medial preoptic area on application of norepinephrine and phenoxybenzamine in free moving rats. Brain Res 1984; 322:322-5. [PMID: 6509320 DOI: 10.1016/0006-8993(84)90125-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The study makes an attempt to find out the action of norepinephrine (NE) and phenoxybenzamine (PB), applied at medial preoptic area (mPOA), in altering the sleep-awake responses, in free moving rats, which has not yet been reported. Effects of application of NE during day and PB during night, at mPOA, on sleep-awake responses, were compared with application of saline during identical periods. Application of NE produced arousal, whereas, PB produced the opposite effect. The findings are suggestive of the involvement of NE terminals at mPOA in normal arousal.
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Kalichman MW, Burnham WM, Livingston KE. Pharmacological investigation of gamma-aminobutyric acid (GABA) and fully-developed generalized seizures in the amygdala-kindled rat. Neuropharmacology 1982; 21:127-31. [PMID: 7063109 DOI: 10.1016/0028-3908(82)90151-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The effects of GABA-modulating drugs were assessed in a pharmacological study of amygdala-kindled seizures in the rat. Fully-kindled subjects were tested with a randomized dose regimen, including drug vehicle, for each of seven drugs. Afterdischarge duration, motor seizure latency, motor seizure duration and motor seizure stage were scored. The GABA synthesis inhibitor, 3-mercaptopropionic acid, the GABA antagonist, bicuculline, and the chloride ionophore blocker, picrotoxin, all decreased motor seizure latency, but did not otherwise alter the kindled seizure duration or seizure stage. The inhibitor of GABA metabolism, gamma-vinyl-GABA, and pentobarbital, which competes for the picrotoxin binding site, both antagonized kindled seizures. Gamma-vinyl-GABA, however, did not appear to antagonize kindled seizures by a specific effect on GABA neurotransmission. The GABA agonists, imidazole acetic acid and [alpha-(chloro-4'phenyl)fluoro-5-hydroxy-2-benzylidene-amino]-4-butyramide (SL 76-002), did not alter the kindled seizures. The results of these experiments are not consistent with the hypothesis that kindled seizures result from a loss of GABA-mediated inhibition; however, GABA may have a role in the modulation of kindled seizure activity.
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MacMillan V. The effects of imidazole-4-acetic acid upon the energy metabolism of normoxic and hypoxic rat brain. Brain Res 1982; 232:439-48. [PMID: 7188030 DOI: 10.1016/0006-8993(82)90286-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The metabolic effects of intravenous administration of 200 mg/kg imidazole-4-acetic acid (IMA) on normoxic, hypoxemic and hypoxemic-oligemic rat brain were assessed by measurement of the cerebral contents of energy phosphates and selected glycolytic-citric acid cycle intermediates. In normoxic brain IMA was associated with unaltered adenylates, increased glucose and aspartate, and decreased pyruvate, lactate, citrate, alpha-ketoglutarate and malate; a pattern which is compatible with cerebral metabolic depression. In hypoxemic brain IMA was associated with a lower accumulation of lactate and a higher level of tissue glucose; again conforming to patterns documented for classical cerebral depressants. In hypoxemic-oligemic brain IMA was associated with a gross deterioration of the tissue ATP content and with a massive lactacidosis which indicated a detrimental action in this hypoxic state.
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Winters WD. A review of the continuum of drug-induced states of excitation and depression. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 1982; 26:225-58. [PMID: 6755557 DOI: 10.1007/978-3-0348-7111-2_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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19
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Fariello RG, Golden GT, Black JA. Activating effects of homotaurine and taurine on corticoreticular epilepsy. Epilepsia 1981; 22:217-24. [PMID: 6781894 DOI: 10.1111/j.1528-1157.1981.tb04104.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Homotaurine and taurine are two powerful inhibitory aminoacids with anticonvulsant properties against various experimental models of focal epilepsy. This study reports on their effects in the feline model of corticoreticular epilepsy induced by parenteral administration of large amounts of penicillin. Both aminoacids, but particularly homotaurine, remarkably potentiate epileptiform discharges in cats. Brainstem transection at the precollicular level does not modify the activation, thus ruling out the intervention of mesoromboencephalic structures in the observed effect. The opposing action of these two amino acids on focal epilepsy as compared to corticoreticular epilepsy suggests that the two types of epileptiform activity stem from very different pathophysiological mechanisms. Homotaurine is a powerful GABA agonist that exerts a central action upon parenteral administration. Other GABA analogs such as muscimol, imidazole acetic acid, and gamma-hydroxybutyrate have been reported to potentiate experimental models of spike and wave epilepsy. Thus, the activating effects of homotaurine in this epilepsy model are in keeping with the demonstrated GABAmimetic properties of the compound.
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Roberts E, Wong E, Svenneby G, Degener P. Sodium-dependent binding of GABA to mouse brain particles. Brain Res 1978; 152:614-9. [PMID: 80248 DOI: 10.1016/0006-8993(78)91119-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Hori N, Ikeda K, Roberts E. Muscimol, GABA and picrotoxin: effects on membrane conductance of a crustacean neuron. Brain Res 1978; 141:364-70. [PMID: 626908 DOI: 10.1016/0006-8993(78)90207-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Beaven MA, Horakova Z, Keiser HR. Interference with histamine and imidazole acetic acid metabolism by salicylates: a possible contribution to salicylate analgesic activity? EXPERIENTIA 1976; 32:1180-2. [PMID: 1085705 DOI: 10.1007/bf01927614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In man, rats and mice, the urinary excretion of the histamine and L-histidine metabolite, imidazole acetic acid, is increased and that of the conjugated metabolite, ribosylimidazole acetic acid, decreased by small doses of salicylates. In contrast to salicylates, other non-salicylate anti-inflammatory drugs, indomethacin, phenylbutazone, phenacetin and acetaminophen do not influence the excretion of the urinary metabolites of histamine and L-histidine. Since imidazole acetic acid is reported to have analgesic and narcotic activity, there is the inference that the analgesic properties of salicylate might be due in part to interference in imidazole acetic acid metabolism.
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24
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Tunnicliff G. Centrally-acting drugs and the formation of brain gamma-aminobutyric acid. GENERAL PHARMACOLOGY 1976; 7:259-62. [PMID: 976740 DOI: 10.1016/0306-3623(76)90085-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
1. The effects of a number of centrally-acting compoinds were tested on the levels of GABA and glutamate and on the formation of GABA from glutamate in rat brain. 2. Pargyline and desipramine increased the brain concentration of GABA but were without effect on GABA production. 3. Imidazoleacetic acid increased GABA levels, decreased glutamate levels but did not alter GABA production, whereas gamma-hydroxybutyric acid had an effect only on GABA formation. 4. Isonicotinc acid hydrazine caused a marked decrease in the formation of GABA from glutamate. 5. Chlorpromazine, diphenylhydantoin, bicucculine, and L-DOPA had no effect on any of the biochemical parameters measured. 6. The central effects of these drugs are discussed in relation to the above findings.
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Rubenstein AD. Massachusetts Medical Society. Impact of the regulatory process on medical practice in Massachusetts. N Engl J Med 1975; 293:504. [PMID: 1152867 DOI: 10.1056/nejm197509042931016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Maśliński C. Histamine and its metabolism in mammals. Part II: Catabolism of histamine and histamine liberation. AGENTS AND ACTIONS 1975; 5:183-225. [PMID: 78663 DOI: 10.1007/bf02026434] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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27
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Constanti A, Quilliam JP. A comparison of the effects of GABA and imidazoleacetic acid on the membrane conductance of lobster muscle fibres. Brain Res 1974; 79:306-10. [PMID: 4153889 DOI: 10.1016/0006-8993(74)90422-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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28
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Benton D, Kyriacou CP, Rick JT, Taberner PV. Behavioural interactions between imidazoleacetic acid and gamma-hydroxybutyric acid in rats and mice. Eur J Pharmacol 1974; 27:288-93. [PMID: 4425346 DOI: 10.1016/0014-2999(74)90003-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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29
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30
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Swagel MW, Ikeda K, Roberts E. Effects of GABA, imidazoleacetic acid, and related substances on conductance of crayfish abdominal stretch receptor. NATURE: NEW BIOLOGY 1973; 246:91-2. [PMID: 4519111 DOI: 10.1038/newbio246091a0] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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31
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Blanco I, Blanco M, Grau M, Palacios JM, Picatoste F, Scherk G. Distribution of histamine in 7 brain regions in different species and strains of mammals. EXPERIENTIA 1973; 29:791-3. [PMID: 4724698 DOI: 10.1007/bf01946288] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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32
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Van Balgooy JN, Roberts E. Methods for study of imidazole compounds and application to brain and cancer cells. Biochem Pharmacol 1973; 22:1405-15. [PMID: 4126030 DOI: 10.1016/0006-2952(73)90318-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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33
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34
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Clifford JM, Taberner PV, Tunnicliff G, Rick JT, Kerkut GA. Biochemical and pharmacological actions of imidazoleacetic acid. Biochem Pharmacol 1973; 22:535-42. [PMID: 4691880 DOI: 10.1016/0006-2952(73)90296-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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35
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36
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Van Balgooy JN, Marshall FD, Roberts E. Metabolism of intracerebrally administered histidine, histamine and imidazoleacetic acid in mice and frogs. J Neurochem 1972; 19:2341-53. [PMID: 4540539 DOI: 10.1111/j.1471-4159.1972.tb01288.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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37
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Tunnicliff G, Wein J, Roberts E. Effects of imidazoleacetic acid on brain amino acids and body temperature in mice. J Neurochem 1972; 19:2017-23. [PMID: 5072379 DOI: 10.1111/j.1471-4159.1972.tb05111.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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38
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Taberner PV, Rick JT, Kerkut GA. The action of gamma-hydroxybutyric acid on cerebral glucose metabolism. J Neurochem 1972; 19:245-54. [PMID: 5010074 DOI: 10.1111/j.1471-4159.1972.tb01334.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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