Immunocytochemical mapping of endomorphin-2-immunoreactivity in rat brain

摘要: Abstract Endomorphin-2 (Tyr-Pro-Phe-Phe-NH 2 ) is a novel endogenous opioid with high affinity and selectivity for the μ-opioid receptor. Immunocytochemical studies have located this peptide in spinal cord, brainstem selected brain regions. However, there are disagreements regarding its distribution between published reports. Furthermore, distributions reported endomorphins resemble that of neuropeptide FF, suggesting some previous findings might be due to cross-reactivity latter substance. In present study, endomorphin-2-immunoreactivity (ir) was examined throughout entire rat using an affinity-purified antiserum appeared not cross-react FF. Endomorphin-2-ir cell somata were most prominent hypothalamus nucleus solitary tract (NTS). varicose fibers observed such areas as bed stria terminalis, septal nuclei, periaqueductal gray, locus coeruleus, lateral parabrachial nucleus, NTS, substantia gelatinosa medulla. More modest immunoreactivity seen nigra, raphe magnus, ventral tegmental area, pontine nuclei amygdala. Fibers also cerebellum. Of note negligible striatum, region known express levels receptors. Thus, endomorphin-2-ir widely, but uniformly, distributed central nervous system associated largely, exclusively, regions expressing Based on distribution, it may role control neuroendocrine, cardiovascular respiratory functions, mood, feeding, sexual behavior pain.