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Effects of sex and ovarian hormones on the initial renal sympathetic nerve activity response to myocardial infarction.
MedLine Citation:
PMID:  22562810     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The physiological mechanisms contributing to sex differences following myocardial infarction (MI) are poorly understood. Given the strong relationship between sympathetic nerve activity (SNA) and outcome, we hypothesized there may be a sex difference in SNA responses to MI. In anesthetized, open chest male, female and ovariectomized female (OVX female) Wistar rats mean arterial pressure (MAP), heart rate (HR), and renal SNA were recorded in response to ligation of the left coronary artery. In males, renal SNA increased by 30±6% in the first minute of coronary occlusion (P<0.05) and remained elevated at 18±7% above baseline (P<0.05) at two hours following MI. In response to MI ovary-intact females displayed no change in renal SNA, whereas OVX females displayed a significant increase, similar to that seen in the males (increases of 43±11% at 1min and 21±7% at 2 hours post MI, P<0.05 vs. intact females). Arterial baroreflex control of renal SNA had a smaller range in females (ovary-intact and OVX) than males; no changes in arterial baroreflex responses were observed one-hour post-MI in males or females. Denervating the arterial baroreceptors abolished the renal SNA response to MI in the males, whereas in ovary-intact females and OVX females the response was unaltered. These findings suggest that ovarian hormones are able to blunt the initial sympathetic activation post-MI in females and that the importance of the arterial baroreflex in mediating initial sympathetic activation post-MI is different between the sexes.
Authors:
Max I Pinkham; Sarah-Jane Guild; Simon Malpas; Carolyn Barrett
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-5-4
Journal Detail:
Title:  Experimental physiology     Volume:  -     ISSN:  1469-445X     ISO Abbreviation:  -     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-5-7     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
University of Auckland.
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