Endomorphin peptides: pharmacological and functional implications of these opioid peptides in the brain of mammals. Part one.

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Bibliographic Details
Title:	Endomorphin peptides: pharmacological and functional implications of these opioid peptides in the brain of mammals. Part one.
Authors:	Gelman, Philippe Leff¹ pleff@imp.edu.mx, Herrera, Norma Estela González², Ortega, Maura Epifanía Matus¹, Romero, Lenin Pavón³, Santillán, Carlos Téllez³, Juárez, Alberto Salazar¹, Palma, Benito Antón¹
Source:	Salud Mental. mar2010, Vol. 33 Issue 2, p179-196. 18p. 2 Diagrams, 2 Charts.
Subjects:	PEPTIDES, AMINO acids, OPIOID receptors, DRUG receptors, BRAIN chemistry, BOS
Abstract (English):	The present paper describes several aspects of the biological activities, physiological and behavioral responses displayed by the most recent discovered opioid peptides: endomorphins. Endormorphins comprise two endogenous C-terminal amide tetrapeptides, named as endomorphin-1 (EM1; Tyr-Pro-Trp-Phe-NH2) and endomorphin-2 (EM2; Tyr-Pro-Phe-Phe-NH2), which were discovered a decade ago (1997) by Zadina's group. Initially, they reported the identification of two endogenous opioid peptides that displayed high binding affinities and selectivities for the μ-opioid receptor among other identified and cloned opioid receptors. These led authors to support the hypothesis that endomorphin peptides represent the endogenous ligand agonists for the μ-opioid receptor. Both peptides were identified and isolated from bovine and human brains. They consist of four amino acids that share a 75% structural homology among amino acids, and which display the structural μ-amidated form of C-terminal -Phe- residue, as demonstrated for many other bioactive neuropeptides. These peptides are structurally distinct from other endogenous opioid substances identified in the brain of mammals, although they share some similarities with other amide terapeptides such as Tyr-WMIF- 1, found also in the mammalian brain. Here, we review the structure-relationship activity of both endomorphin molecules comparing their binding properties to different opioid receptors. Both EM1/EM2 peptides appear to be vulnerable to enzymatic degradation when exposed to the activities of different proteolytic enzymes, as occurs with many other neuroactive peptides found in the SNC of mammals. Immunohistochemical studies showed the wide and asymmetric distribution of both EM1-2 peptides in the brain, leading to the extensive pharmacological, cellular, and physiological studies that demonstrated the wide and varied bioactivities displayed by these peptides at both central and peripheral tissues. These studies led several authors to suggest the potential endogenous role of these peptides in major physiological processes (e.g. analgesia or antinociception). Based on the generation of specific (rabbit) polyclonal antibodies and the use of combined radioimmunoassay (RIA) techniques and immunohistochemical procedures, it was shown the wide distribution of EM1-2-LI (endomorphin1-2-like immunoreactivities) throughout the brain of different species (e.g. rat, primate, human), particularly co-localized in specific areas where μ-opioid receptor has been shown to be expressed.… [ABSTRACT FROM AUTHOR]
Abstract (Spanish):	Este artículo resume varios aspectos de las múltiples actividades biológicas, celulares, efectos farmacológicos, respuestas fisiológicas y conductuales de dos nuevas sustancias peptídicas de naturaleza opioide, descubiertas recientemente y denominadas endomorfinas. Las endomorfinas son dos péptidos opioides, clasificados como endomorfina-1 (EM1, Tyr-Pro-Trp-Phe-NH2) y endomorfina-2 (EM2, Tyr-Pro-Phe-Phe-NH2), cuyas secuencias peptídicas fueron identificadas y aisladas del cerebro de bovino y humano por el grupo de Zadina en 1997. Estudios de unión radioligando-receptor demostraron que estos péptidos se unen con alta afinidad de unión al receptor opioide μen relación con su capacidad de unión a otros subtipos de receptores opioides (kappa [κ], delta [δ]), previamente identificados en el SNC de mamíferos. Ambos péptidos están compuestos por cuatro aminoácidos y son estructuralmente distintos de las demás sustancias opioides endógenas conocidas. Esta revisión detalla con precisión diversos aspectos de la farmacología y actividades celulares de estos opioides y sus implicaciones en la modulación de distintas circuitos o vías neurales y funcionamiento del SNC de los mamíferos, respectivamente. Los estudios relacionados con la función estructura-actividad de estos péptidos han mostrado que, al igual que la mayoría de los péptidos bioactivos endógenos de naturaleza opioide y no opioide, son vulnerables a la escisión peptídica por cortes enzimáticos mediante la exposición a distintas enzimas proteolíticas que pudiesen participar en la degradación endógena de las endomorfinas, y la obtención de diversos productos de degradación. Asimismo, este artículo menciona la amplia distribución neuroanatómica que poseen las endomorfinas en distintas regiones del cerebro, particularmente en aquellas que regulan el procesamiento y la transmisión de la información nociceptiva y que, por tanto, reflejan el papel potencial de estos péptidos en procesos fisiológicos de analgesia, entre muchos otros (memoria y otro aprendizaje). En este contexto, diferentes estudios basados en el empleo de ensayos inmunológicos (radioinmunoensayos [RIA] y técnicas de inmunohistoquímica [IHC]) que requieren el uso de anticuerpos específicos generados contra las secuencias consenso de las endomorfinas mostraron una amplia distribución de material inmunoreactivo a endomorfina (vg., EM1-LI, EM2-LI) en tejidos neurales de humano, bovino y roedores. … [ABSTRACT FROM AUTHOR]
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Database:	MedicLatina

Description
Abstract:	The present paper describes several aspects of the biological activities, physiological and behavioral responses displayed by the most recent discovered opioid peptides: endomorphins. Endormorphins comprise two endogenous C-terminal amide tetrapeptides, named as endomorphin-1 (EM1; Tyr-Pro-Trp-Phe-NH2) and endomorphin-2 (EM2; Tyr-Pro-Phe-Phe-NH2), which were discovered a decade ago (1997) by Zadina's group. Initially, they reported the identification of two endogenous opioid peptides that displayed high binding affinities and selectivities for the μ-opioid receptor among other identified and cloned opioid receptors. These led authors to support the hypothesis that endomorphin peptides represent the endogenous ligand agonists for the μ-opioid receptor. Both peptides were identified and isolated from bovine and human brains. They consist of four amino acids that share a 75% structural homology among amino acids, and which display the structural μ-amidated form of C-terminal -Phe- residue, as demonstrated for many other bioactive neuropeptides. These peptides are structurally distinct from other endogenous opioid substances identified in the brain of mammals, although they share some similarities with other amide terapeptides such as Tyr-WMIF- 1, found also in the mammalian brain. Here, we review the structure-relationship activity of both endomorphin molecules comparing their binding properties to different opioid receptors. Both EM1/EM2 peptides appear to be vulnerable to enzymatic degradation when exposed to the activities of different proteolytic enzymes, as occurs with many other neuroactive peptides found in the SNC of mammals. Immunohistochemical studies showed the wide and asymmetric distribution of both EM1-2 peptides in the brain, leading to the extensive pharmacological, cellular, and physiological studies that demonstrated the wide and varied bioactivities displayed by these peptides at both central and peripheral tissues. These studies led several authors to suggest the potential endogenous role of these peptides in major physiological processes (e.g. analgesia or antinociception). Based on the generation of specific (rabbit) polyclonal antibodies and the use of combined radioimmunoassay (RIA) techniques and immunohistochemical procedures, it was shown the wide distribution of EM1-2-LI (endomorphin1-2-like immunoreactivities) throughout the brain of different species (e.g. rat, primate, human), particularly co-localized in specific areas where μ-opioid receptor has been shown to be expressed.… [ABSTRACT FROM AUTHOR]
ISSN:	01853325