Positive allosteric modulators (PAMs), negative allosteric modulators (NAMs), silent agonists, al... more Positive allosteric modulators (PAMs), negative allosteric modulators (NAMs), silent agonists, allosteric activating PAMs and neutral or silent allosteric modulators are compounds capable of modulating the nicotinic receptor by interacting at allosteric modulatory sites distinct from the orthosteric sites. This survey is focused on the compounds that have been shown or have been designed to interact with nicotinic receptors as allosteric modulators of different subtypes, mainly α7 and α4β2. Minimal chemical changes can cause a different pharmacological profile, which can then lead to the design of selective modulators. Experimental evidence supports the use of allosteric modulators as therapeutic tools for neurological and non-neurological conditions.
In this study, a new series of heterodimers was synthesized. These derivatives are N,N-bis(alkano... more In this study, a new series of heterodimers was synthesized. These derivatives are N,N-bis(alkanol)amine aryl esters or N,N-bis(ethoxyethanol)amine aryl esters carrying a methoxylated aryl residue combined with a flavone or chromone moiety. The new compounds were studied to evaluate their P-gp modulating activity on a multidrug-resistant leukemia cell line. Some of the new compounds show a good MDR reversing activity; interestingly this new series of compounds does not comply with the structure-activity relationships (SAR) outlined by previously synthesized analogs carrying different aromatic moieties. In the case of the compounds described in this paper, activity is linked to different features, in particular the characteristics of the spacer, which seem to be critical for the interaction with the pump. This fact indicates that the presence of a flavone or chromone residue influences the SAR of these series of products, and that flexible molecules can find different productive bind...
A series of N-alkanol- N-cyclohexanol amine aryl esters cis/ trans isomers that showed high effic... more A series of N-alkanol- N-cyclohexanol amine aryl esters cis/ trans isomers that showed high efficacy to reverse the acquired resistance of cancer cells during chemotherapeutic therapy (MDR mechanism) was studied. These compounds were two 1,4 cyclohexane cis/ trans derivatives (named ELF26A and ELF26B, respectively), and their positional isomers (named ELF34A and ELF34B, respectively) where the aryl-moieties were exchanged. In order to evaluate the behaviour of these compounds during biological tests, a method based on liquid chromatography coupled with mass spectrometry (LC-MS), operating in tandem mass spectrometry (MS/MS) mode, was developed. A unique chromatographic method suitable to separate the two pairs of cis/ trans isomers was not achieved and the MS/MS experiments of the different compounds was not always able to characterise the different isomers. Therefore, a system of linear equations of deconvolution analysis (LEDA) tool was proposed to determine the relative proportio...
The enantiomers of the potent cognition-enhancer DM232 ((1), unifiram) and of its isopropylsulfon... more The enantiomers of the potent cognition-enhancer DM232 ((1), unifiram) and of its isopropylsulfonyl analog (2), which is endowed with amnesic properties, have been synthesized using (S)- and (R)-5-(hydroxymethyl)-2-pyrrolidinone as chiral precursors. The enantiomeric excess was determined by means of capillary electrophoresis, and found higher than 99.9 %. DM232 enantiomers were tested as cognition-enhancers in the passive-avoidance and social learning tests, and their ability to induce ACh release from rat cerebral cortex was also determined; in all the performed essays, (R)-(+)-(1) displayed higher potency than its (S)-(-) enantiomer, being able to elicit comparable effects at 3-fold to 10-fold lower doses. On the contrary, (R)-(+) and (S)-(-)-(2) showed the same amnesic potency when tested in the passive-avoidance test. These findings may be useful to clarify the mechanism of action of these substances.
Positive allosteric modulators (PAMs), negative allosteric modulators (NAMs), silent agonists, al... more Positive allosteric modulators (PAMs), negative allosteric modulators (NAMs), silent agonists, allosteric activating PAMs and neutral or silent allosteric modulators are compounds capable of modulating the nicotinic receptor by interacting at allosteric modulatory sites distinct from the orthosteric sites. This survey is focused on the compounds that have been shown or have been designed to interact with nicotinic receptors as allosteric modulators of different subtypes, mainly α7 and α4β2. Minimal chemical changes can cause a different pharmacological profile, which can then lead to the design of selective modulators. Experimental evidence supports the use of allosteric modulators as therapeutic tools for neurological and non-neurological conditions.
In this study, a new series of heterodimers was synthesized. These derivatives are N,N-bis(alkano... more In this study, a new series of heterodimers was synthesized. These derivatives are N,N-bis(alkanol)amine aryl esters or N,N-bis(ethoxyethanol)amine aryl esters carrying a methoxylated aryl residue combined with a flavone or chromone moiety. The new compounds were studied to evaluate their P-gp modulating activity on a multidrug-resistant leukemia cell line. Some of the new compounds show a good MDR reversing activity; interestingly this new series of compounds does not comply with the structure-activity relationships (SAR) outlined by previously synthesized analogs carrying different aromatic moieties. In the case of the compounds described in this paper, activity is linked to different features, in particular the characteristics of the spacer, which seem to be critical for the interaction with the pump. This fact indicates that the presence of a flavone or chromone residue influences the SAR of these series of products, and that flexible molecules can find different productive bind...
A series of N-alkanol- N-cyclohexanol amine aryl esters cis/ trans isomers that showed high effic... more A series of N-alkanol- N-cyclohexanol amine aryl esters cis/ trans isomers that showed high efficacy to reverse the acquired resistance of cancer cells during chemotherapeutic therapy (MDR mechanism) was studied. These compounds were two 1,4 cyclohexane cis/ trans derivatives (named ELF26A and ELF26B, respectively), and their positional isomers (named ELF34A and ELF34B, respectively) where the aryl-moieties were exchanged. In order to evaluate the behaviour of these compounds during biological tests, a method based on liquid chromatography coupled with mass spectrometry (LC-MS), operating in tandem mass spectrometry (MS/MS) mode, was developed. A unique chromatographic method suitable to separate the two pairs of cis/ trans isomers was not achieved and the MS/MS experiments of the different compounds was not always able to characterise the different isomers. Therefore, a system of linear equations of deconvolution analysis (LEDA) tool was proposed to determine the relative proportio...
The enantiomers of the potent cognition-enhancer DM232 ((1), unifiram) and of its isopropylsulfon... more The enantiomers of the potent cognition-enhancer DM232 ((1), unifiram) and of its isopropylsulfonyl analog (2), which is endowed with amnesic properties, have been synthesized using (S)- and (R)-5-(hydroxymethyl)-2-pyrrolidinone as chiral precursors. The enantiomeric excess was determined by means of capillary electrophoresis, and found higher than 99.9 %. DM232 enantiomers were tested as cognition-enhancers in the passive-avoidance and social learning tests, and their ability to induce ACh release from rat cerebral cortex was also determined; in all the performed essays, (R)-(+)-(1) displayed higher potency than its (S)-(-) enantiomer, being able to elicit comparable effects at 3-fold to 10-fold lower doses. On the contrary, (R)-(+) and (S)-(-)-(2) showed the same amnesic potency when tested in the passive-avoidance test. These findings may be useful to clarify the mechanism of action of these substances.
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