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Colocalization and shared distribution of endomorphins with substance P, calcitonin gene‐related peptide, γ‐aminobutyric acid, and the mu opioid receptor
Author(s) -
Greenwell Thomas N.,
MartinSchild Sheryl,
Inglis Fiona M.,
Zadina James E.
Publication year - 2007
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.21374
Subject(s) - colocalization , calcitonin gene related peptide , biology , opioid receptor , neuropeptide , receptor , neuroscience , medicine , parabrachial nucleus , μ opioid receptor , orphan receptor , endocrinology , microbiology and biotechnology , nucleus , opioid , biochemistry , gene , transcription factor
The endomorphins are endogenous opioids with high affinity and selectivity for the mu opioid receptor (MOR, MOR‐1, MOP). Endomorphin‐1 (Tyr‐Pro‐Trp‐Phe‐NH 2 ; EM1) and endomorphin‐2 (Tyr‐Pro‐Phe‐Phe‐NH 2 ; EM2) have been localized to many regions of the central nervous system (CNS), including those that regulate antinociception, autonomic function, and reward. Colocalization or shared distribution (overlap) of two neurotransmitters, or a transmitter and its cognate receptor, may imply an interaction of these elements in the regulation of functions mediated in that region. For example, previous evidence of colocalization of EM2 with substance P (SP), calcitonin gene‐related peptide (CGRP), and MOR in primary afferent neurons suggested an interaction of these peptides in pain modulation. We therefore investigated the colocalization of EM1 and EM2 with SP, CGRP, and MOR in other areas of the CNS. EM2 was colocalized with SP and CGRP in the nucleus of the solitary tract (NTS) and with SP, CGRP and MOR in the parabrachial nucleus. Several areas in which EM1 and EM2 showed extensive shared distributions, but no detectable colocalization with other signaling molecules, are also described. J. Comp. Neurol. 503:319–333, 2007. Published 2007 Wiley‐Liss, Inc.