title: Endomorphin1-like immunoreactivity in the limbic system of Syrian hamsters (Mesocricetus auratus).
abstract: Recently, endomorphin-1 (Tyr-Pro-Trp-Phe-NH2; EM1), an endogenous peptide that has high affinity and selectivity for the mu-opiate receptor, has been shown to modulate emotional behavior in mice and social behavior in Syrian hamsters. Endomorphin-1 (EM1) is present throughout the central nervous system in rats, mice, and guinea pigs; however, the distribution of EM1 in hamsters has not been described. The purpose of the present study was to investigate the distribution of EM1-like immunoreactivity (EM1L-IR) in the limbic system of Syrian hamsters using immunocytochemistry. Perikarya containing EM1L-IR were present in the anterior area, dorsomedial, ventromedial, periventricular, posterior, and arcuate nuclei of the hypothalamus. Fibers expressing EM1L-IR were present in the nucleus accumbens, caudate putamen, septum, bed nucleus of the stria terminalis, amygdaloid complex, and hypothalamus. The distribution of EM1 suggests a potential endogenous role for this peptide in major processes modulated by opiates, including affective states and social behavior.
authors.affiliation: Center for Behavioral Neuroscience, Department of Psychology, Georgia State University, Atlanta, GA 30303, USA.
authors.forename: R D
authors.initials: RD
authors.lastname: Whitten
authors.forename: S
authors.initials: S
authors.lastname: Martin-Schild
authors.forename: J E
authors.initials: JE
authors.lastname: Zadina
authors.forename: H E
authors.initials: HE
authors.lastname: Albers
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D001522:Behavior, Animal / Q000502:physiology; D006224:Cricetinae; D004644:Emotions / Q000502:physiology; D007150:Immunohistochemistry; D008032:Limbic System / Q000166:cytology / Q000378:metabolism*; D008647:Mesocricetus / Q000033:anatomy & histology / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism*; D012919:Social Behavior
chemical_list: D009842:Oligopeptides; C105293:endomorphin 1