Endomorphin peptides: pharmacological and functional implications of these opioid peptides in the brain of mammals. Part two
| Autor: | Philippe Leff Gelman, Norma Estela González Herrera, Maura Epifanía Matus Ortega, Enrique Beceril Villanueva, Carlos Téllez Santillán, Alberto Salazar Juárez, Benito Antón Palma |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: | |
| Zdroj: | Instituto Politécnico Nacional IPN Redalyc-IPN Salud Mental (México) Num.3 Vol.33 |
| Popis: | "Endomorphin-1 (EM1) and Endomorphin-2 (EM2) represent the two endogenous C-terminal amide tetrapeptides shown to display a high binding affinity and selectivity for the u-opioid receptor as reported previously (see previous paper, Part I). Endomorphins injected into the VTA were shown to enhance the development of behavioral sensitization responses to amphetamine (AMPH), besides of inducing an increase of locomotion (horizontal) activity in animals. These studies showed that EM2 was significantly more potent than EM1 in modulating the increased opioid-mediated ambulatory responses by altering the dopamine (DA) projecting system in the globus pallidus in tested animals. Several transmission systems (e.g., GABA) have been shown to participate in the endormorphin-induced locomotor responses. EM1 injected into the VTA produced potent rewarding effects in rodents, similar to the rewarding responses produced by distinct opiate compounds. The opioid rewarding responses induced by EM1-2 were shown to be mediated via the activation of both GABAergic and the dopamine (VTA-NAc-PFCx) transmission systems in the brain. Moreover, EM1-2 peptides injected into the VTA, but not in the NAc, produced similar related-rewarding responses induced by low doses of morphine. However, ICV administration of EM1 was shown to enhance a significant conditioned-place preference (CPP); whereas EM2 displayed a place aversion in tested animals." |
| Databáze: | OpenAIRE |
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