Document Detail


Melanocortin 3/4 Receptors in Paraventricular Nucleus Modulates Sympathetic Outflow and Blood Pressure.
MedLine Citation:
PMID:  22872662     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
Central melanocortin 3/4 receptors (MC3/4R) are known to regulate energy balance. Activation of the MC3/4R causes greater increase in the firing activity of the PVN neurons in obese Zucker rats than in lean Zucker rats. The present study was to determine the roles of MC3/4R in hypothalamus paraventricular nucleus (PVN) in modulating the sympathetic activity and blood pressure and its downstream pathway. Renal sympathetic nerve activity (RSNA) and mean arterial pressure (MAP) were recorded in anesthetized rats. Microinjection of MC3/4R agonist melanotan II (MTII) into the PVN increased the RSNA and MAP. The MC3/4R antagonist agouti-related peptide (AgRP) or SHU9119 decreased the RSNA and MAP, but the MC4R antagonist HS024 had no significant effect on the RSNA and MAP. The effects of MTII were abolished by the PVN pretreatment with AgRP, SHU9119, adenylate cyclase (AC) inhibitor SQ22536, or protein kinase A (PKA) inhibitor Rp-cAMP, and substantially attenuated by HS024. The SQ22536 alone in the PVN had no significant effect on the RSNA and MAP, but Rp-cAMP caused significant decreases in the RSNA and MAP. Furthermore, MTII increased cAMP level in the PVN. These results indicate that MC3/4R activation in the PVN increases the sympathetic outflow and blood pressure via cAMP-PKA pathway. MC3R in the PVN may exert a tonic excitatory effect on sympathetic activity.
Authors:
Peng Li; Bai-Ping Cui; Ling-Li Zhang; Hai-Jian Sun; Tong-Yan Liu; Guo-Qing Zhu
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-8-7
Journal Detail:
Title:  Experimental physiology     Volume:  -     ISSN:  1469-445X     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2012 Aug 
Date Detail:
Created Date:  2012-8-8     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Nanjing Medical University.
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