ABSTRACT
The rostral ventromedial medulla (RVM) is a prominent component of the descending modulatory system involved in the control of spinal nociceptive transmission. In the current study, we investigated melanocortin-4 receptor (MC4R) expression in the RVM, where the neurons involved in modulation of nociception reside. Using a line of mice expressing green fluorescent protein (GFP) under the control of the MC4R promoter, we found a large number of GFP-positive neurons in the RVM [nucleus raphe magnus (NRM) and nucleus gigantocellularis pars α (NGCα)]. Fluorescence immunohistochemistry revealed that approximately 10% of MC4R-GFP-positive neurons coexpressed tyrosine hydroxylase, indicating that they were catecholaminergic, whereas 50%-75% of those coexpressed tryptophan hydroxylase, indicating that they were serotonergic. Our findings support the hypothesis that MC4R signaling in RVM may modulate the activity of serotonergic sympathetic outflow sensitive to nociceptive signals, and that MC4R signaling in RVM may contribute to the descending modulation of nociceptive transmission.
ABSTRACT
The rostral ventromedial medulla (RVM) is a prominent component of the descending modulatory system involved in the control of spinal nociceptive transmission. In the current study, we investigated melanocortin-4 receptor (MC4R) expression in the RVM, where the neurons involved in modulation of nociception reside. Using a line of mice expressing green fluorescent protein (GFP) under the control of the MC4R promoter, we found a large number of GFP-positive neurons in the RVM [nucleus raphe magnus (NRM) and nucleus gigantocellularis pars α (NGCα)]. Fluorescence immunohistochemistry revealed that approximately 10% of MC4R-GFP-positive neurons coexpressed tyrosine hydroxylase, indicating that they were catecholaminergic, whereas 50%-75% of those coexpressed tryptophan hydroxylase, indicating that they were serotonergic. Our findings support the hypothesis that MC4R signaling in RVM may modulate the activity of serotonergic sympathetic outflow sensitive to nociceptive signals, and that MC4R signaling in RVM may contribute to the descending modulation of nociceptive transmission.
Subject(s)
Animals , Female , Male , Mice , Medulla Oblongata , Cell Biology , Metabolism , Mice, Transgenic , Neural Pathways , Cell Biology , Metabolism , Neurons, Afferent , Cell Biology , Metabolism , Nociception , Physiology , Receptor, Melanocortin, Type 4 , Genetics , Metabolism , Serotonergic Neurons , Metabolism , Tyrosine 3-Monooxygenase , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To study the chemical constituents of hybridized Bulbus Fritillariae Ussuriensis.</p><p><b>METHOD</b>The chemical constituents were isolated by silica column chromatography and their structures were identified by physical and chemical eveidences and spectral analysis (IR, 1H-NMR, 13C-NMR, 2D-NMR, MS).</p><p><b>RESULT</b>Seven compounds were obtained and identified as (20S,25S)5alpha, 14alpha, 17beta-cevanine-6beta-hydroxy-3-one (hupehenirine, ZF1), (20S,25S)5alpha, 14alpha, 17beta-cevanine-3beta-hydroxy-6-one (hupehenizine, ZF2), (20R,25S)5alpha, 14alpha-cevanine-3beta,20beta-dihydroxy-6-one (peiminine, verticinone, ZF3), (20S,25S)5alpha, 14alpha, 17beta-cevanine-3beta, 6beta-dihydroxy (hupehenine, ZF4), (20R,25S)5alpha, 14alpha-cevanine-3beta, 6beta, 20beta-trihydroxy (isoverticine, ZF5), (20R,25S)5alpha, 14alpha-cevanine-3beta, 6alpha, 20beta-trihydroxy (peimine, verticine, ZF6), (20S,25S)5alpha, 14alpha, 17beta-evanine-6beta-hydroxy-3beta-O-beta-D-glucoside (hupeheninoside, ZF7).</p><p><b>CONCLUSION</b>Compounds ZF1-7 were isolated from hybridized Bulbus Fritillariae Ussuriensis for the first time.</p>