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ICER and c‐Fos expression in the hindbrain following central administration of U‐50488 (U‐50), a selective kappa opioid agonist
Author(s) -
Gottlieb Helmut B,
Ji Lisa,
Martinez Michelle,
Little Joel T,
Cunningham J Thomas
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a509-a
Subject(s) - area postrema , hindbrain , endocrinology , medicine , κ opioid receptor , brainstem , solitary tract , agonist , lateral parabrachial nucleus , premovement neuronal activity , c fos , chemistry , receptor , central nervous system , neuroscience , biology , parabrachial nucleus , gene expression , biochemistry , gene
Central kappa opioid administration produces a marked increase in renal sympathetic nerve activity with a concurrent water diuresis in conscious rats. Because kappa opioid agonists produce their neuronal inhibitory effects in part via the inhibition of cAMP through Gi/o, they may also change the expression of endogenous transcriptions factors involved in suppression of cAMP regulated transcription factors. Thus, inducible cAMP early repressor (ICER) staining may serve as a neuronal marker for the activation of 2 nd messenger systems that suppress cAMP regulated genes. The present study examines the effects of intracerebroventricular (ICV) U‐50 (10 μg/5μl) on ICER and c‐Fos staining in several hindbrain regions that express kappa binding sites and are also involved in sympathetic outflow. Alternate sets of brainstem sections were processed for ICER using polyclonal anti‐ICER antibody raised in rabbit and c‐Fos using a commercially available antibody. Sections were also double labeled with DBH to anatomically define these regions. ICV U‐50 produced significant increases in ICER staining in the medial (VEH, 8 ± 4; U50 24 ± 4; P < .001) and anterior (VEH, 3 ± 3; U50 12 ± 3; P < .05) nucleus of the solitary tract, area postrema (VEH, 2.1± 1.9; U‐50 41 ± 14; P < .001), and locus coeruleus (VEH, 1.3± .7; U‐50 23± 10; P < .001). In contrast to ICER, c‐Fos expression only decreased in the area postrema without any significant changes in the other hindbrain regions. Together, central kappa opioid receptor mediated responses in these hindbrain regions may contribute to the central effects of U‐50. Supported by NIH HL62579 & DK57822 .