RESUMEN
Although agonists and antagonists of muscarinic receptors have been known for long time, there is renewed interest in compounds (such as allosteric or bitopic ligands, or biased agonists) able to differently and selectively modulate these receptors. As a continuation of our previous research, we designed a new series of dimers of the well-known cholinergic agonist carbachol. The new compounds were tested on the five cloned human muscarinic receptors (hM1-5) expressed in CHO cells by means of equilibrium binding experiments, showing a dependence of the binding affinity on the length and position of the linker connecting the two monomers. Kinetic binding studies revealed that some of the tested compounds were able to slow the rate of NMS dissociation, suggesting allosteric behavior, also supported by docking simulations. Assessment of ERK1/2 phosphorylation on hM1, hM2 and hM3 activation showed that the new compounds are endowed with muscarinic antagonist properties. At hM2 receptors, some compounds were able to stimulate GTPγS binding but not cAMP accumulation, suggesting a biased behavior. Classification, Molecular and cellular pharmacology.
Asunto(s)
Carbacol/farmacología , Agonistas Muscarínicos/farmacología , Antagonistas Muscarínicos/farmacología , Receptores Muscarínicos/efectos de los fármacos , Animales , Células CHO , Carbacol/química , Carbacol/metabolismo , Cricetulus , AMP Cíclico/metabolismo , Dimerización , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Guanosina 5'-O-(3-Tiotrifosfato)/metabolismo , Humanos , Cinética , Simulación del Acoplamiento Molecular , Estructura Molecular , Agonistas Muscarínicos/química , Agonistas Muscarínicos/metabolismo , Antagonistas Muscarínicos/química , Antagonistas Muscarínicos/metabolismo , Fosforilación , Unión Proteica , Receptores Muscarínicos/genética , Receptores Muscarínicos/metabolismo , Transducción de Señal , Relación Estructura-ActividadRESUMEN
A three-dimensional database search has been applied to design a series of endo- and exo-3-(pyridin-3-yl)bicyclo[2.2.1]heptan-2-amines as nicotinic receptor ligands. The synthesized compounds were tested in radioligand binding assay on rat cortex against [3H]-cytisine and [3H]-methyllycaconitine to measure their affinity for α4ß2* and α7* nicotinic receptors. The new derivatives showed some preference for the α4ß2* over the α7* subtype, with their affinity being dependent on the endo/exo isomerism and on the methylation degree of the basic nitrogen. The endo primary amines displayed the lowest Ki values on both receptor subtypes. Selected compounds (1a, 2a, 3a, and 6a) were tested on heterologously expressed α4ß2, α7, and α3ß2 receptors and on SHSY-5Y cells. Compounds 1a and 2a showed α4ß2 antagonistic properties while behaved as full agonists on recombinant α7 and on SHSY5Y cells. On the α3ß2 subtype, only the chloro derivative 2a showed full agonist activity and submicromolar potency (EC50 = 0.43 µM). The primary amines described here represent new chemotypes for the α7 and α3* receptor subtypes.
Asunto(s)
Agonistas Nicotínicos/farmacología , Norbornanos/farmacología , Piridinas/farmacología , Receptores Nicotínicos/metabolismo , Receptor Nicotínico de Acetilcolina alfa 7/metabolismo , Aminas/síntesis química , Aminas/farmacología , Animales , Línea Celular Tumoral , Corteza Cerebral/metabolismo , Diseño de Fármacos , Humanos , Simulación del Acoplamiento Molecular , Agonistas Nicotínicos/síntesis química , Antagonistas Nicotínicos/síntesis química , Antagonistas Nicotínicos/farmacología , Norbornanos/síntesis química , Piridinas/síntesis química , RatasRESUMEN
Nicotinic receptors are membrane proteins involved in several physiological processes. They are considered suitable drug targets for various CNS disorders or conditions, as shown by the large number of compounds which have entered clinical trials. In recent years, nonconventional agonists have been discovered: positive allosteric modulators, allosteric agonists, site-specific agonists and silent desensitizers are compounds able to modulate the receptor interacting at sites different from the orthodox one, or to desensitize the receptor without prior opening. While these new findings can further complicate the pharmacology of these proteins and the design and optimization of ligands, they undoubtedly offer new opportunities to find drugs for the many therapeutic indications involving nicotinic receptors.
Asunto(s)
Enfermedades del Sistema Nervioso Central/tratamiento farmacológico , Diseño de Fármacos , Agonistas Nicotínicos/farmacología , Agonistas Nicotínicos/uso terapéutico , Antagonistas Nicotínicos/farmacología , Antagonistas Nicotínicos/uso terapéutico , Receptores Nicotínicos/metabolismo , Regulación Alostérica/efectos de los fármacos , Animales , Enfermedades del Sistema Nervioso Central/metabolismo , Humanos , Ligandos , Estructura Molecular , Agonistas Nicotínicos/síntesis química , Agonistas Nicotínicos/química , Antagonistas Nicotínicos/síntesis química , Antagonistas Nicotínicos/químicaRESUMEN
1. Oxybutynin hydrochloride is an antimuscarinic agent prescribed to patients with an overactive bladder (OAB) and symptoms of urinary urge incontinence. Oxybutynin undergoes pre-systemic metabolism, and the N-desethyloxybutynin (Oxy-DE), is reported to have similar anticholinergic effects. 2. We revisited the oxidative metabolic fate of oxybutynin by liquid chromatography-tandem mass spectrometry analysis of incubations with rat and human liver fractions, and by measuring plasma and urine samples collected after oral administration of oxybutynin in rats. This investigation highlighted that not only N-deethylation but also N-oxidation participates in the clearance of oxybutynin after oral administration. 3. A new metabolic scheme for oxybutynin was delineated, identifying three distinct oxidative metabolic pathways: N-deethylation (Oxy-DE) followed by the oxidation of the secondary amine function to form the hydroxylamine (Oxy-HA), N-oxidation (Oxy-NO) followed by rearrangement of the tertiary propargylamine N-oxide moiety (Oxy-EK), and hydroxylation on the cyclohexyl ring. 4. The functional activity of Oxy-EK was investigated on the muscarinic receptors (M1-3) demonstrating its lack of antimuscarinic activity. 5. Despite the presence of the α,ß-unsaturated function, Oxy-EK does not react with glutathione indicating that in the clearance of oxybutynin no reactive and potentially toxic metabolites were formed.
Asunto(s)
Cetonas/metabolismo , Ácidos Mandélicos/metabolismo , Pargilina/análogos & derivados , Propilaminas/metabolismo , Administración Oral , Animales , Cromatografía Liquida , Glucurónidos/metabolismo , Humanos , Masculino , Ácidos Mandélicos/sangre , Ácidos Mandélicos/química , Ácidos Mandélicos/orina , Espectrometría de Masas , Redes y Vías Metabólicas , Microsomas Hepáticos/metabolismo , Oxidación-Reducción , Pargilina/química , Pargilina/metabolismo , Propilaminas/química , Ratas Sprague-Dawley , Ratas Wistar , Receptores Muscarínicos/metabolismoRESUMEN
A series of homodimers of the well-known cholinergic agonist carbachol have been synthesized, showing the two agonist units symmetrically connected through a methylene chain of variable length. The new compounds have been tested on the five cloned muscarinic receptors (hM1-5) expressed in CHO cells by means of equilibrium binding studies, showing an increase in affinity by rising the number of methylene units up to 7 and 9. Functional experiments on guinea-pig ileum and assessment of ERK1/2 phosphorylation on hM1, hM2 and hM3 on CHO cells have shown that the new compounds are endowed with muscarinic antagonistic properties. Kinetic binding studies have revealed that some of the tested compounds are able to slow the rate of dissociation of NMS, suggesting a bitopic behavior. Docking simulations, performed on the hM1 and hM2 receptors, give a sound rationalization of the experimental data revealing how these compounds are able to interact with both orthosteric and allosteric binding sites depending on the length of their connecting chain.
Asunto(s)
Carbacol/análogos & derivados , Carbacol/farmacología , Antagonistas Muscarínicos/farmacología , Animales , Sitios de Unión , Células CHO , Carbacol/química , Cricetulus , Dimerización , Cobayas , Humanos , Íleon/efectos de los fármacos , Íleon/fisiología , Masculino , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Simulación del Acoplamiento Molecular , Contracción Muscular , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Fosforilación , Ensayo de Unión Radioligante , Relación Estructura-ActividadRESUMEN
As a continuation of previous work on quinoline derivatives, which showed some preference (2-3 times) for the α7 with respect to α4ß2 acetylcholine nicotinic receptors (nAChRs), we synthesized a series of novel azabicyclic or diazabicyclic compounds carrying a quinoline or isoquinoline ring, with the aim of searching for more selective α7 nAChR compounds. Radioligand binding studies on α7* and α4ß2* nAChRs (rat brain homogenate) revealed one compound (7) with a 2-fold higher affinity for the α4ß2*-subtype, and four compounds (11, 13, 14 and 16) with at least 3-fold higher affinity for α7* nAChR. The most promising was 11, showing Kiâ¼100 nM and over 10-fold selectivity for α7* nAChR. Compounds 7, 11, 13 and 16 at 50 µM suppressed ion currents induced in the rat α4ß2 nAChR and the chimeric nAChR composed of the ligand-binding domain of the chick α7 and transmembrane domain of the α1 glycine receptor, expressed in Xenopus oocytes. Calcium imaging experiments on the human α7 nAChR expressed in the Neuro2a cells and potentiated by PNU-120596 confirmed the antagonistic activity for 7; on the contrary, 11, 13 and 16 were agonists with the EC50 values in the range of 1.0-1.6 µM. Thus, the introduced modifications allowed us to enhance the selectivity of quinolines towards α7 nAChR and to get novel compounds with agonistic activity.
Asunto(s)
Quinolinas/química , Quinolinas/farmacología , Receptores Nicotínicos/metabolismo , Receptor Nicotínico de Acetilcolina alfa 7/metabolismo , Animales , Compuestos Bicíclicos con Puentes/síntesis química , Compuestos Bicíclicos con Puentes/química , Compuestos Bicíclicos con Puentes/farmacología , Calcio/metabolismo , Línea Celular Tumoral , Humanos , Ratones , Simulación del Acoplamiento Molecular , Nicotina/análogos & derivados , Nicotina/síntesis química , Nicotina/farmacología , Agonistas Nicotínicos/síntesis química , Agonistas Nicotínicos/química , Agonistas Nicotínicos/farmacología , Antagonistas Nicotínicos/síntesis química , Antagonistas Nicotínicos/química , Antagonistas Nicotínicos/farmacología , Quinolinas/síntesis química , Ratas , Xenopus , Receptor Nicotínico de Acetilcolina alfa 7/agonistas , Receptor Nicotínico de Acetilcolina alfa 7/antagonistas & inhibidoresRESUMEN
BACKGROUND: Recurrent ipsilateral ovarian torsion at pediatric age is a rare event. Different surgical techniques for its prevention are available. We present a case of recurrent ipsilateral ovarian torsion in a prepubertal girl and we reviewed the literature about the management of this condition. CASE: A 6-year-old girl presented with right ovarian torsion and underwent a laparoscopic untwisting. Nine months later an ipsilateral recurrence occurred. Laparoscopic untwisting and right-sided oophoropexy with plication to the round ligament was performed. SUMMARY AND CONCLUSION: In addition to our presented case, four cases of recurrent ipsilateral ovarian torsion in pediatric patients were identified in the literature. The few available reports in the pediatric literature show different management techniques. A long-term study is necessary to define the most effective treatment.
Asunto(s)
Laparoscopía/métodos , Enfermedades del Ovario/cirugía , Anomalía Torsional/cirugía , Niño , Femenino , Humanos , Imagen por Resonancia Magnética , Enfermedades del Ovario/diagnóstico , Recurrencia , Anomalía Torsional/diagnóstico , Ultrasonografía Doppler en ColorRESUMEN
Cellulose represents a key component of a renewable biomass source, from which chiral compounds with a high added value in the application for the synthesis of potentially bioactive molecules can be obtained. The anhydrosugar (1R,5S)-1-hydroxy-3,6-dioxa-bicyclo[3.2.1]octan-2-one (LAC), produced on the gram-scale by catalytic pyrolysis of cellulose, was used as a building block in the synthesis of five new enantiomerically pure muscarine-like products. The structures of the target compounds 4-8 showed different substituents at the C-2 and C-4 positions, but each of them had the same (2S,4R) configuration as the natural (+)-muscarine. A renewed interest in new muscarinic analogues is due to the design and synthesis of molecules exhibiting a higher selectivity for a specific muscarinic receptor and due to the development of effective agents in the treatment of Alzheimer's disease and other cognitive disorders. In this context, products 4-8 were investigated with respect to their binding affinity to human M1-M5 muscarinic acetylcholine receptors. The data indicated that compound 8, emerging as the most active in the series with values comparable to natural (+)-muscarine and a moderate selectivity in favor of the hM2 subtype receptor, also exhibited the highest stability during the interaction with the hM2 (3UON) subtype muscarinic receptor by using a docking calculation.
Asunto(s)
Compuestos Bicíclicos Heterocíclicos con Puentes/química , Celulosa/química , Muscarina/síntesis química , Estructura Molecular , Muscarina/química , EstereoisomerismoRESUMEN
As a continuation of our research on potent and efficacious P-gp-dependent multidrug resistance (MDR) reversers, several new N,N-bis(alkanol)amine aryl esters were designed and synthesized, varying the aromatic moieties or the length of the methylenic chain. The new compounds were tested on doxorubicin-resistant erythroleukemia K562 cells (K562/DOX) in the pirarubicin uptake assay, where most of the new compounds were shown to be active. In particular the asymmetrical compounds, characterized by two linkers of different length, generally showed fairly high activities as MDR reversers. Some selected compounds (isomers 15-17) were further studied by evaluating their doxorubicin cytotoxicity enhancement (reversal fold, RF) on the K562/DOX cell line. The results of both pharmacological assays indicate that compounds 16 (GDE6) and 17 (GDE19) could be interesting leads for the development of new P-gp dependent MDR modulators.
Asunto(s)
Aminas/química , Aminas/farmacología , Aminas/síntesis química , Antineoplásicos/metabolismo , Transporte Biológico/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Doxorrubicina/análogos & derivados , Doxorrubicina/metabolismo , Resistencia a Múltiples Medicamentos/efectos de los fármacos , Resistencia a Antineoplásicos/efectos de los fármacos , Ésteres , Humanos , Isomerismo , Células K562RESUMEN
As a continuation of previous research on a new series of potent and efficacious P-gp-dependent multidrug resistant (MDR) reversers with a N,N-bis(cyclohexanol)amine scaffold, we have designed and synthesized several analogs by modulation of the two aromatic moieties linked through ester functions to the N,N-bis(cyclohexanol)amine, aiming to optimize activity and to extend structure-activity relationships (SAR) within the series. This scaffold, when esterified with two different aromatic carboxylic acids, gives origin to four geometric isomers (cis/trans, trans/trans, cis/cis and trans/cis). The new compounds were tested on doxorubicin-resistant erythroleukemia K562 cells (K562/DOX) in the pirarubicin uptake assay. Most of them resulted in being potent modulators of the extrusion pump P-gp, showing potency values ([I](0.5)) in the submicromolar and nanomolar range. Of these, compounds 2b, 2c, 3d, 5a-d and 6d, showed excellent efficacy with a α(max) close to 1. Selected compounds (2d, 3a, 3b, 5a-d) were further studied to evaluate their doxorubicin cytotoxicity potentiation (RF) on doxorubicin-resistant erythroleukemia K562 cells and were found able to enhance significantly doxorubicin cytotoxicity on K562/DOX cells. The results of both pirarubicin uptake and the cytotoxicity assay, indicate that the new compounds of the series are potent P-gp-mediated MDR reversers. They present a structure with a mix of flexible and rigid moieties, a property that seems critical to allow the molecules to choose the most productive of the several binding modes possible in the transporter recognition site. In particular, compounds 5c and 5d, similar to the already reported analogous isomers 1c and 1d,(29) are potent and efficacious modulators of P-gp-dependent MDR and may be promising leads for the development of MDR-reversal drugs.
Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/antagonistas & inhibidores , Aminas/química , Antineoplásicos/química , Ciclohexanoles/química , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Antineoplásicos/síntesis química , Antineoplásicos/toxicidad , Supervivencia Celular/efectos de los fármacos , Doxorrubicina/toxicidad , Resistencia a Antineoplásicos , Ésteres , Humanos , Isomerismo , Células K562 , Relación Estructura-ActividadRESUMEN
Starting from the structure of previously studied muscarinic agonists, characterized by a pyrrolidinylfuran scaffold, a new series of muscarinic antagonists was synthesized by substituting the 5-position of the furane cycle with bulky hydrophobic groups. Both tertiary amines and the corresponding iodomethyl derivatives were obtained and studied. All the new compounds show high affinity toward cloned human muscarinic M(1)-M(5) receptors expressed in Chinese hamster ovary (CHO) cells and behave as competitive antagonists on classical models of muscarinic receptors. The diastereoisomeric mixture of the highest affinity compound of the series was resolved into the four optical isomers by chiral HPLC. The relative and absolute configuration of the obtained compounds was established by means of a combined strategy based on X-ray crystallography and chiroptical techniques. Although generally fairly potent, the compounds showed only modest subtype selectivity, with the exception of 2a and 6a, which in functional assays presented clear-cut selectivity for the muscarinic receptors present in rabbit vas deferens.
Asunto(s)
Furanos/farmacología , Antagonistas Muscarínicos/síntesis química , Antagonistas Muscarínicos/farmacología , Pirroles/farmacología , Receptores Muscarínicos/metabolismo , Animales , Células CHO , Cricetinae , Cricetulus , Cristalografía por Rayos X , Furanos/síntesis química , Furanos/química , Cobayas , Humanos , Masculino , Modelos Moleculares , Estructura Molecular , Antagonistas Muscarínicos/química , Pirroles/síntesis química , Pirroles/química , Conejos , Estereoisomerismo , Relación Estructura-Actividad , Conducto Deferente/metabolismoRESUMEN
Pirenzepine (2) is one of the most selective muscarinic M(1) versus M(2) receptor antagonists known. A series of 2 analogs, in which the piperazyl moiety was replaced by a cis- and trans-cyclohexane-1,2-diamine (3-6) or a trans- and cis-perhydroquinoxaline rings (7 and 8) were prepared, with the aim to investigate the role of the piperazine ring of 2 in the interaction with the muscarinic receptors. The structural change leading to compounds 3-6 abolished in binding assays the muscarinic M(1)/M(2) selectivity of 2, due to an increased M(2) affinity. Rather, compounds 3-6 displayed a reversed selectivity showing more affinity at the muscarinic M(2) receptor than at all the other subtypes tested.
Asunto(s)
Ciclohexilaminas/química , Antagonistas Muscarínicos/química , Antagonistas Muscarínicos/farmacología , Pirenzepina/análogos & derivados , Pirenzepina/química , Quinoxalinas/química , Animales , Células CHO , Cricetinae , Cricetulus , Regulación de la Expresión Génica , Cobayas , Atrios Cardíacos/efectos de los fármacos , Humanos , Masculino , Modelos Moleculares , Estructura Molecular , Músculo Esquelético/metabolismo , Pirenzepina/farmacología , Unión Proteica , Conejos , Receptores Muscarínicos/metabolismo , Relación Estructura-Actividad , Conducto Deferente/efectos de los fármacosRESUMEN
Building on the previously and successfully applied hypothesis that stereochemical complication in the proximity of the critical cationic head of a cholinergic agonist would result in subtype selective compounds, we synthesized a series of chiral derivatives of furmethide and 5-methylfurmethide, with the aim of obtaining compounds that are useful for treating diseases derived from cholinergic receptor dysfunctions and/or useful for further characterizing subtypes of cholinergic receptors. Unlike their parent compounds, the new molecules lack nicotinic activity, being pure muscarinic ligands. While binding studies on the five cloned human muscarinic receptors showed no subtype selectivity, functional assays revealed that some of the molecules of the series are potent M 2 selective partial agonists with interesting pharmacological profiles.
Asunto(s)
Furanos/síntesis química , Furanos/farmacología , Agonistas Muscarínicos/síntesis química , Agonistas Muscarínicos/farmacología , Pirroles/química , Animales , Células CHO , Dicroismo Circular , Cricetinae , Cricetulus , Cristalografía por Rayos X , Furanos/química , Cobayas , Humanos , Pulmón/efectos de los fármacos , Masculino , Modelos Moleculares , Estructura Molecular , Agonistas Muscarínicos/química , Conejos , Espectrofotometría , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Completing a long-lasting research on 1,3-oxathiolane muscarinic ligands, we have synthesized a set of isomeric 1-methyl-2-(2,2-alkylaryl-1,3-oxathiolan-5-yl)pyrrolidine 3-sulfoxide derivatives, containing three or four stereogenic centers. In general the compounds are very potent antagonists even if, unlike the corresponding agonists, they show modest subtype selectivity.
Asunto(s)
Antagonistas Muscarínicos/síntesis química , Antagonistas Muscarínicos/farmacología , Pirrolidinas/síntesis química , Pirrolidinas/farmacología , Sulfóxidos/síntesis química , Sulfóxidos/farmacología , Animales , Sitios de Unión , Células CHO , Células Cultivadas , Cricetinae , Cricetulus , Relación Dosis-Respuesta a Droga , Cobayas , Ligandos , Masculino , Modelos Moleculares , Estructura Molecular , Antagonistas Muscarínicos/química , Pirrolidinas/química , Conejos , Receptores Muscarínicos/efectos de los fármacos , Estereoisomerismo , Relación Estructura-Actividad , Sulfóxidos/químicaRESUMEN
The aim of the present paper was to investigate the role of the octamethylene spacer of methoctramine (1) on the biological profile. Thus, this spacer was incorporated into a dianiline or dipiperidine moiety to determine whether flexibility and the basicity of the inner nitrogen atoms are important determinants of potency with respect to muscarinic receptors. The most potent compound was 4, which displayed, in the functional assays, a comparable potency at muscarinic M(2) receptors with respect to 1, and, in the binding assays, a loss of potency and selectivity toward muscarinic M(1) and M(3) receptor subtypes. Both compounds were endowed with antinociceptive activity. Furthermore, in microdialysis tests in rat parietal cortex, they enhanced acetylcholine release, most likely by antagonizing presynaptic muscarinic receptor subtypes.
Asunto(s)
Diaminas/química , Diseño de Fármacos , Antagonistas Muscarínicos/farmacología , Poliaminas/farmacología , Acetilcolina/metabolismo , Acetilcolinesterasa/química , Acetilcolinesterasa/metabolismo , Animales , Butirilcolinesterasa/química , Butirilcolinesterasa/metabolismo , Células CHO/efectos de los fármacos , Corteza Cerebral/efectos de los fármacos , Inhibidores de la Colinesterasa/síntesis química , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/farmacología , Cricetinae , Cricetulus , Evaluación Preclínica de Medicamentos , Cobayas , Atrios Cardíacos/efectos de los fármacos , Atrios Cardíacos/metabolismo , Humanos , Íleon/efectos de los fármacos , Íleon/metabolismo , Masculino , Ratones , Estructura Molecular , Antagonistas Muscarínicos/síntesis química , Antagonistas Muscarínicos/química , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Lóbulo Parietal/efectos de los fármacos , Etiquetas de Fotoafinidad , Poliaminas/síntesis química , Poliaminas/química , Conejos , Ensayo de Unión Radioligante , Ratas , Receptores Muscarínicos/clasificación , Receptores Muscarínicos/efectos de los fármacos , Relación Estructura-Actividad , Conducto Deferente/efectos de los fármacos , Conducto Deferente/metabolismoRESUMEN
Starting from a previously studied muscarinic ligand, characterized by a 1,3-oxathiolane nucleus, a new series of muscarinic antagonists were designed by increasing the stereochemical complexity of the molecules. A small library of enantiomeric and diastereomeric 2,2-diphenyl- and 2-cyclohexyl-2-phenyl substituted compounds was thus obtained. All the tested compounds show a high affinity toward cloned human muscarinic hm1-hm5 receptors expressed in CHO cells and a good antagonistic activity on functional assays, with a modest selectivity on rabbit vas deferens.
Asunto(s)
Antagonistas Muscarínicos/síntesis química , Pirrolidinas/síntesis química , Tiofenos/síntesis química , Animales , Células CHO , Cricetinae , Cricetulus , Cobayas , Humanos , Íleon/efectos de los fármacos , Íleon/fisiología , Técnicas In Vitro , Masculino , Antagonistas Muscarínicos/química , Antagonistas Muscarínicos/farmacología , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Contracción Miocárdica/efectos de los fármacos , Pirrolidinas/química , Pirrolidinas/farmacología , Conejos , Ensayo de Unión Radioligante , Receptores Muscarínicos/metabolismo , Estereoisomerismo , Relación Estructura-Actividad , Tiofenos/química , Tiofenos/farmacología , Conducto Deferente/efectos de los fármacos , Conducto Deferente/fisiologíaRESUMEN
By further steric complication of previously studied highly chiral muscarinic agonists, we have obtained a small chiral library of enantiomeric and diasteromeric 1-methyl-2-(2-methyl-1,3-oxathiolan-5-yl)pyrrolidine 3-sulfoxides. Binding studies on cloned human muscarinic receptors expressed in CHO cells show that the introduction of a fourth stereogenic center gives undetectable affinity for hm1, hm3, hm4 and hm5 subtypes while leaving a quite modest affinity only for hm2 subtypes. However, functional studies on model M1-M4 muscarinic tissues have shown that three compounds of the series [(-)-5, (-)-7, (+)-8] are endowed with functional activity and behave as M2 selective partial agonists. Among them, compound (2S,2'R,3'S,5'R)-1-methyl-2-(2-methyl-1,3-oxathiolan-5-yl)pyrrolidine 3-sulfoxide methyl iodide [(+)-8] is particularly interesting, as it is a potent partial agonist on guinea pig atrium (force) (M2; pD2=7.65, alpha=0.41) while being a poor antagonist on M1, M3, and M4 model tissues (pKb<5).
Asunto(s)
Óxidos S-Cíclicos/síntesis química , Pirrolidinas/síntesis química , Receptor Muscarínico M2/agonistas , Animales , Función del Atrio Izquierdo/efectos de los fármacos , Células CHO , Cricetinae , Cricetulus , Óxidos S-Cíclicos/química , Óxidos S-Cíclicos/farmacología , Cobayas , Humanos , Íleon/efectos de los fármacos , Íleon/fisiología , Técnicas In Vitro , Ligandos , Pulmón/efectos de los fármacos , Pulmón/fisiología , Masculino , Contracción Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Músculo Liso/fisiología , Pirrolidinas/química , Pirrolidinas/farmacología , Conejos , Estereoisomerismo , Relación Estructura-Actividad , Conducto Deferente/efectos de los fármacos , Conducto Deferente/fisiologíaRESUMEN
Starting from two previously studied muscarinic full agonists, characterized by a 1,3-dioxolane ((+)-1) and a 1,3-oxathiolane ((+)-2) cycle, two new series of muscarinic ligands were designed, obtained by the steric complication of the parent compounds produced by freezing the aminoalkyl chain into a pyrrolidine ring. Both tertiary amines and the corresponding iodomethyl derivatives were synthesised and studied, and several compounds of the series which behaved as muscarinic agonists have been selected, on the basis of preliminary binding experiments on rat cortex homogenates, for the present work. Results are presented obtained from testing the affinity of the selected compounds against cloned human muscarinic receptors expressed in CHO cells, in order to evaluate subtype selectivity. Their functional activity on classical models of M1-M4 receptors, in guinea pig and rabbit tissues is also reported. With respect to parent compounds, the new molecules present some selectivity toward hm2 receptors; fair M2 selectivity is also evident in functional studies, where these compounds behave as partial agonists. Among the other compounds of the series (2S, 4'R, 2'S)-1,1-dimethyl-2-(2-methyl-1,3-dioxolan-4-yl)pyrrolidinium iodide (-)-3 and (2R, 5'S, 2'S)-1-methyl-2-(2-methyl-1,3-oxathiolan-5-yl)pyrrolidine (+)-5 present a promising pharmacological profile. Compound (-)-3 shows modest hm2 selectivity in binding experiments but a clearcut M2 selectivity in functional tests, where it behaves as a weak antagonist on M1 and M4 subtypes, as a weak full agonist on the M3 subtype and as a potent partial agonist on M2 subtype. Tertiary amine (+)-5 presents a quite similar profile but appears more interesting since, lacking a permanent charge on the nitrogen atom, it may represent an interesting tool to study CNS muscarinic receptors. Our results confirm that sterical complication of parent compounds (+)-1 and (+)-2 produces more selective muscarinic agonists.
Asunto(s)
Agonistas Muscarínicos/farmacología , Antagonistas Muscarínicos/farmacología , Pirrolidinas/farmacología , Receptores Muscarínicos/fisiología , Animales , Células CHO , Cricetinae , Cobayas , Humanos , Técnicas In Vitro , Masculino , Agonistas Muscarínicos/química , Antagonistas Muscarínicos/química , Unión Proteica/efectos de los fármacos , Unión Proteica/fisiología , Isoformas de Proteínas/agonistas , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/fisiología , Pirrolidinas/química , Conejos , Relación Estructura-ActividadRESUMEN
The synthesis and preliminary pharmacological profile of a new series of muscarinic antagonists, derived from previously studied 2,2-diphenyl-2-ethylthio-acetic acid esters, are reported. The parent molecules were decorated with linkers of different length, carrying an amino group to catch a putative anionic function outside the recognition site of the receptor. It was hoped that the interception of this function would give molecules with higher potency and selectivity. The attempt has not been successful, but a new series of compounds with a peculiar pharmacological profile has been identified.
Asunto(s)
Ácido Acético/síntesis química , Ácido Acético/metabolismo , Diseño de Fármacos , Antagonistas Muscarínicos/síntesis química , Antagonistas Muscarínicos/metabolismo , Animales , Sitios de Unión/fisiología , Células CHO , Cricetinae , Ésteres , Cobayas , Humanos , Técnicas In Vitro , Masculino , Conformación Molecular , ConejosRESUMEN
Several compounds with a 4-aminopiperidine scaffold decorated on both nitrogen atoms by alkyl or acyl moieties containing the structural motifs of verapamil and of flunarizine, as well as those that are more frequent in known N-type calcium channel antagonists, have been synthesized. Antinociceptive activity on the mouse hot-plate test was used to select molecules to be submitted to further studies. Active compounds were tested in vitro on a PC12 rat pheochromocytoma clonal cell line, to evaluate their action on N-type calcium channels, and on a rat model of neuropathic pain. Two compounds that show N-type calcium channel antagonism and are endowed with potent action on pain and neuropathic pain (3 and 18) have been selected for further studies.