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At least 19 recordsLinked to original sources
PubMed1982

Effects of phenothiazines and dibenzazepines on axonal transport and microtubule assembly in vitro.

Various phenothiazines (thioridazine, trifluoperazine and chlorpromazine) and dibenzazepines (lofepramine, amitriptyline and desipramine) were studied for effects on fast axonal transport (AXT) in vitro in frog sciatic nerves. AXT, measured as the accumulation of (3H) leucine-labelled proteins in front of a ligature, was inhibited by more then 50% by all the drugs tested at 0.2 mM concentrations. Thioridazine and lofepramine were the most potent inhibitors. These effects were not due to decreased ganglionic incorporation. Some of the drugs also reduced the levels of high energy phosphates, adenosinetriphosphate (ATP) and creatinephosphate (CrP), but not to an extent which is likely to explain the arrested AXT. The polymerization of purified brain tubulin was inhibited by the phenothiazines but unaffected by the dibenzazepines at concentrations which inhibited AXT. Phenothiazines and dibenzazepines are chemically related and known to have a high affinity for calmodulin. The possibility that these drugs interefere with calmodulin regulated processes of importance for AXT will be discussed.

Adenosine Triphosphate↗
PubMed2001

Hexamethonium-type allosteric modulators of the muscarinic receptors bearing lateral dibenzazepine moieties.

Alkane-bisammonium compounds carrying lateral phthalimido substituents are known to have a high affinity for the allosteric binding site of the acetylcholine M2 receptor. The purpose of this study was to replace the lateral phthalimido moieties with rigid tricyclic skeletons of a large volume in order to learn more about the function of the lateral heterocycles. In addition, methyl groups were introduced into the lateral connecting chains. Allosteric inhibition of the dissociation of [3H]N-methylscopolamine from the M2 receptors in porcine cardiac homogenates served to indicate binding of the test compounds to the allosteric site. The phthalimido groups could be replaced with dibenzazepine moieties without any loss in potency. Interestingly, the additional methyl group in the lateral spacer seems to have a significant influence on the allosteric behaviour.

Allosteric Regulation↗
PubMed1995

Peroxidase-catalysed oxidation of different dibenzazepine derivatives.

According to a recent hypothesis suggesting the potential role of free radical formation in the clozapine-induced agranulocytosis, we have evaluated the susceptibility to the peroxidase-mediated oxidation of different dibenzazepine analogues. On the one hand, compounds with an arylamine group such as clozapine or isoclozapine present a high reactivity in the horseradish peroxidase or myeloperoxidase systems and, on the other hand, fluperlapine, though known to induce agranulocytosis, and other dibenzothiazepine and dibenzoxazepine derivatives appear insensitive to oxidation. Consequently, among tricyclic derivatives, the way of diaryloxa- and diarylthiazepine compounds could be an alternative for the development of safer drugs such as antipsychotics.

Catalysis↗
PubMedDate not supplied

Chromatographic modelling of interactions between melanin and phenothiazine and dibenzazepine drugs.

Differences in drug-melanin interactions were determined for 13 phenothiazine neuroleptics and 2 dibenzazepine thymoleptics by means of high-performance liquid chromatography. The chromatographic column was packed with a stationary phase obtained by chemical immobilization of synthetic L-dopa melanin on silica particles. For six phenothiazines the melanin-binding parameters were also determined by an ultrafiltration method. Correlation between measures of drug-melanin interaction determined chromatographically and by the standard slow-equilibrium method was significant, however moderate. The chromatographic method of assessing interactions between drugs and melanin permitted reliable and quantitatively comparable data for representative series of solutes to be readily obtained. Such data were subjected to the analysis of quantitative structure-retention relationships (QSRR). It was found that retention of the agents on the immobilized melanin column could be described by two-parameter regression equations comprising the energy of the lowest unoccupied molecular orbital and either the water-accessible surface area of a drug molecule or its hydrophobicity parameter, determined chromatographically on an immobilized artificial membrane column. The QSRR equation derived allows for the estimation of melanin binding based on the structure of a compound candidate, and thus rationalizes predictions of potential toxicity of drugs or drug candidates.

Antidepressive Agents↗
PubMed2004

2,2'-Bipyridine as a new and sensitive spectrophotometric reagent for the determination of nanoamounts of certain dibenzazepine class of tricyclic antidepressant drugs.

2,2'-bipyridine is proposed as new and sensitive spectrophotometric reagent for the determination of certain dibenzazepine class of tricyclic antidepressants. The spectrophotometric method is based on the reaction of imipramine hydrochloride (IPH), desipramine hydrochloride (DPH), clomipramine hydrochloride (CPH), trimipramine maleate (TPM) and opipramol (OPP) with iron (III) and subsequent reaction with 2,2'-bipyridine in an acetic acid medium to yield a pink color with maximum absorption at 530 nm. The color developed was stable over 3-4 h at room temperature (approximately 27 degrees C). The commonly encountered excipients and additives did not interfere with the determination. Results from the analysis of pure drugs and commercial tablets agreed well with those of the official method (United States Pharmacopoeia, 24, USP Convention, Rockville 2000, pp. 505-506, 865-867.).

2,2'-Dipyridyl↗
PubMed1985

The effect of phenothiazine and dibenzazepine pretreatment on the metabolism of methamphetamine in rats.

There was marked variation between p-hydroxylation and N-demethylation of methamphetamine in rats. Within 24 h, 10.4, 24-7 and 4.1% of the administered methamphetamine was excreted in urine unchanged, p-hydroxymethamphetamine (p-OH-MP, free plus conjugated) and also as amphetamine, respectively. Treatment by imipramine, desipramine, chlorpromazine, perphenazine and propericiazine 8 h before the administration with methamphetamine completely inhibited the urinary excretion of p-OH-MP whereas the excretion of amphetamine was enhanced by about 700 to 800%. This effect was also observed in rats treated with imipramine 16 and 24 h before methamphetamine. Phenothiazine and dibenzazepine derivatives reverse the degree of p-hydroxylation and N-demethylation of methamphetamine in-vivo in rats.

Amphetamine↗
PubMed1997

Rational design of selective ligands for trypanothione reductase from Trypanosoma cruzi. Structural effects on the inhibition by dibenzazepines based on imipramine.

Trypanothione reductase, the enzyme which in trypanosomal and leishmanial parasites catalyses the reduction of trypanothione disulphide to the redox-protective dithiol and has been identified as a potential target for rational antiparasite drug design, has been found to be strongly inhibited by tricyclic compounds containing the saturated dibenzazepine (imipramine) nucleus, with Ki values in the low micromolar range. This drug lead structure was designed by molecular graphics analysis of a three-dimensional homology model, focussing on the active-site. Inhibition studies were carried out to determine the effect of inhibitor structure on the inhibitory strength towards recombinant trypanothione reductase from Trypanosoma cruzi. Hansch analysis showed that inhibitory strength depended on terms in pi, pi 2 and sigma m indicating dependence on both lipophilicity and inductive effect for ring-substituted analogues of imipramine. The side-chain omega-aminoalkyl chain had to be longer than 2-carbon units for inhibition. The effect on inhibition strength of the substituent at the omega-amino position on the side-chain of the central ring nitrogen atom depended markedly on the detailed substitution pattern of the rest of the molecule. This provides kinetic evidence studies of multiple binding modes within a single, blanket binding site for the inhibitor with the tricyclic ring system in the general region of the hydrophobic pocket lined by Trp21, Tyr110, Met113 and Phe114. This aspect of the structural sensitivity of the precise active-site triangulation adopted by the inhibitor is probably a function of the use of hydrophobic interactions of low directional specificity in this pocket combined with an electrostatic anchoring by the omega-N+ HMe2 function of the inhibitor, presumably with a glutamate side-chain, such as Glu-18, Glu-466' and/or Glu-467'.

Animals↗
PubMed1992

[Effects of phenothiazine and dibenzazepine derivatives on the muscarinic cholinergic system].

Interactions of some dialkylaminoalkyl (DAL) and dialkylaminoacyl (DAC) derivatives of phenothiazine and dibenzazepine with muscarinic cholinergic receptors (MR) of rabbit striatum and heart and rat brain were investigated. DAC derivatives were more active at brain and heart MR in some cases. The most active preparation was G-512, DA-analogue of chlorpromazine. Some cardiotropic properties of antianginal preparation nonachlazine may be connected with its central antimuscarinic activity.

Animals↗
PubMedDate not supplied

[The interaction of dialkylaminoacyl derivatives of phenothiazine, dibenzazepine and dibenzdiazepine with opiate receptors].

Specific binding of dialkylaminoacyl (DAC) derivatives of phenothiazine, dibenzazepine, dibenzdiazepine with opiate receptors (OR) of mu- and delta-subtypes was studied. Some of the compounds studied exhibit moderate affinity to mu-OR in microM range. Binding with delta-OR is less pronounced. Dibenzdiazepine derivative AL-234 is the most potent compound with respect to OR of both mu- and delta- subtypes (IC50 values were 11 and 60 microM, respectively). The ability of DAC- derivatives to bind specifically OR can play a decisive role in realization of their pharmacologic properties, namely antinociceptive and probably antiarrhythmic activity.

Analgesics↗
PubMed1991

Radioimmunoassay of dibenzazepines and dibenzcycloheptanodienes in body fluids and tissues.

In an attempt to establish a radioimmunoassay (RIA), imipramine and amitriptyline immunogens were prepared; desmethyl derivatives were converted into hemisuccinates, conjugated with bovine serum albumin and used for rabbit immunization. [3H]Amitriptyline (4.3 TBq/mmol) and [3H]imipramine (2.9 TBq/mmol) were prepared by catalytic dehalogenation or reductive alkylation. Dibenzazepines and dibenzcycloheptanodienes were determined in biological fluids by a direct method without deproteinization (lower detection limit of 0.5 microgram.l-1); using high-yield methods they were extracted from cell membranes. Assay of tricyclic antidepressants in humans showed that these substances disappear from plasma much earlier than from cell membranes. Dissociation of the antidepressants bound to cell membranes is slow and their plasma concentrations are not influenced by standing for 2 h at 4 degrees C. During preparing the membranes for binding studies these substances are not removed, and they may affect the results of the binding studies.

Amitriptyline↗
PubMed1977

Synthesis of some dibenzazepines of possible therapeutic interest.

Among the hypotensive drugs are the N-alkyldibenz[c,e]-azepines. A representative of this class is 6-allyl-6,7-dihydro-5H-dibenz[c,e]azepine (azapetine). The present investigation involved the preparation of a new series of N-[6,7-dihydro-5H-dibenz[c,e]azepin-6-yl] acid amides namely; acetamide, benzamide, phehyl acetamide, salicylamide and p-hydroxybenzamide derivatives. Another new series of N-[6,7-dihydro-5H-dibenz[c,e]azepin-6-yl]-N-alkyl (or aryl) thioureas was prepared namely ethyl, isopropyl, butyl, cyclohexyl, benzyl, phenyl and o-tolyl thiourea derivatives. IR spectra of the two series of compounds were investigated.

Antihypertensive Agents↗
PubMed1988

Behavioural and neuropharmacological properties of the dibenzazepines, desipramine and lofepramine: studies on the olfactory bulbectomized rat model of depression.

1. Lofepramine was compared with its major desipramine for its effects on adaptation to novel objects in the home cage (neophobia) and exploratory behaviours in both sham operated and olfactory bulbectomized rats. 2. In the test for neophobia (marble burying), the aversive response of bulbectomized rats differed from that of the sham operated animals, the bulbectomized rats showing a diminished aversive response. This response was unaffected by either antidepressant. 3. Of two tests for exploratory activity, the "open field" test clearly differentiated the bulbectomized rats treated with desipramine from those treated with lofepramine. In the lower doses used (1 and 10 mg/kg), only desipramine treatment significantly attenuated the hypermotility of the bulbectomized rats. In high doses (30 mg/kg), lofepramine also attenuated the hypermotility of the bulbectomized rats; this could have been due to the presence of high concentrations of the desipramine metabolite. In a non-stressful novel environment ('hole board'), neither drug significantly affected the behaviour of sham operated or olfactory bulbectomized rats. Neither antidepressant had noticeable anticholinergic properties as indicated by the number of faecal boli deposited. 4. Acute clonidine administration was found to attenuate the activity of rats in the 'open field' apparatus. This effect was attenuated following the chronic administration of desipramine but not lofepramine. It may be concluded that the pharmacological activity of lofepramine is independent of its metabolism to desipramine in vivo.

Animals↗