RESUMEN
Inflammatory disorders typically have a complex etiology and involve a multitude of inflammatory mediators, and hence, a polytherapeutic approach to these diseases would seem appropriate. In certain chronic inflammatory conditions, we believe that bradykinin (BK) and human neutrophil elastase (HNE) are cooperatively involved. We have previously synthesized compounds with inhibitory activity toward both the BK B2 receptor and HNE. The present study describes single compounds designed to incorporate HNE inhibitory activity and BK B1 and B2 antagonist activity. A proprietary HNE inhibitor (HNEI, CP-955) was directly linked via amide bond formation to a peptide-based combined BK B1/B2 antagonist (B-9430). Three compounds were made using different linking positions in the antagonist peptide. For all compounds, B1 and B2 receptor binding in human cloned receptors was at least 10-fold less than that of B-9430, whereas in the in vitro guinea pig ileum B2 receptor functional assay, the compounds had potencies equivalent to B-9430. Compound I was found to have a fourfold increase in HNEI activity compared with CP-955, whereas compounds II and III were inactive. These data clearly demonstrate that it is possible to retain BK B1/B2 receptor antagonist and HNE activity in a heterodimer.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Antagonistas de los Receptores de Bradiquinina , Inhibidores Enzimáticos/farmacología , Elastasa de Leucocito/antagonistas & inhibidores , Secuencia de Aminoácidos , Animales , Antiinflamatorios no Esteroideos/síntesis química , Antiinflamatorios no Esteroideos/metabolismo , Dimerización , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/metabolismo , Cobayas , Humanos , Técnicas In Vitro , Inflamación/tratamiento farmacológico , Cinética , Receptor de Bradiquinina B1 , Receptor de Bradiquinina B2 , Receptores de Bradiquinina/metabolismoAsunto(s)
Receptores Opioides/efectos de los fármacos , Tirosina/análogos & derivados , Secuencia de Aminoácidos , Animales , Unión Competitiva/efectos de los fármacos , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Cobayas , Datos de Secuencia Molecular , Oligopéptidos/síntesis química , Oligopéptidos/farmacología , Fenilalanina/análogos & derivados , Receptores Opioides/metabolismo , Relación Estructura-ActividadRESUMEN
The highly rigid and conformationally extended 2-amino-4-phosphonobutanoic acid (AP4) analogue (RS)-1-amino-3-(phosphonomethylene)-cyclobutane-1-carboxylic acid (cyclobutylene AP5) was synthesized and found to inhibit evoked responses in the rat lateral perforant path (LPP) with an IC50 of 41 (+/- 1.5 S.E.M.) microM and the medial perforant pathway with an IC50 of 218 (+/- 3.7 S.E.M.) microM. Furthermore, paired pulse potentiation experiments suggest that cyclobutylene AP5 acts, in part, at a presynaptic site in the LPP. Thus, cyclobutylene AP5 appears to act in a similar manner to L-AP4 in the perforant pathway. These data support the hypothesis that L-AP4 assumes an extended conformation at the L-AP4 receptor of the LPP.
Asunto(s)
Ciclobutanos/farmacología , Hipocampo/fisiología , Compuestos Organofosforados/farmacología , Tetragastrina/análogos & derivados , Animales , Ciclobutanos/química , Relación Dosis-Respuesta a Droga , Potenciales Evocados , Técnicas In Vitro , Masculino , Conformación Molecular , Vías Nerviosas/fisiología , Compuestos Organofosforados/química , Concentración Osmolar , Ratas , Ratas Endogámicas , Tetragastrina/administración & dosificación , Tetragastrina/farmacologíaRESUMEN
The cyclopropyl compounds (Z)- and (E)-2-amino-2,3-methano-4-phosphonobutanoic acid, 5 and 6, respectively, were prepared as constrained analogues of 2-amino-4-phosphonobutanoic acid (AP4), a selective glutamate receptor ligand. A Horner-Emmons reaction of trimethyl N-(benzyloxycarbonyl)phosphonoglycinate with 2-(diethoxyphosphinyl)acetaldehyde gave the protected dehydroamino acids 9 and 10, which were individually subjected to the following sequence of reactions: cycloaddition of diazomethane, photoelimination of N2, and acid hydrolysis, to give 5 and 6, respectively. Extracellular recording techniques were used to evaluate the abilities of 5 and 6 to block evoked synaptic transmission in specific neuronal pathways of the rat hippocampal slice. In the lateral perforant path (LPP) 5 and 6 were equipotent and possessed IC50 values of 18 and 17 microM, respectively. In the medial perforant path (MPP), 6 (IC50 = 81 microM) was much more potent than 5 (IC50 = 1580 microM). In paired pulse experiments which differentiate presynaptic and postsynaptic inhibition, 5 and 6 enhanced the second response to the same extent as L-AP4, suggesting a presynaptic site of action for these compounds. In contrast, the cyclopentyl AP4 analogues 3 and 4 enhanced the second response to a lesser extent. It was concluded that the biologically active conformation of AP4 in the LPP is different than in the MPP. In order to explain the same potency of 5 and 6 in the LPP, it was postulated that the two analogues assume a conformation that allows their functional groups to occupy the same relative place in space. Molecular modeling showed that the best overlap was achieved when the alpha C-beta C-gamma C-P dihedral angle for 5 was in the range of 130 degrees to 180 degrees and that of 6 was in the range of -130 degrees to -180 degrees. The results suggest that the bioactive conformation of AP4 in the LPP is an extended one.