Display options
Share it on

Front Physiol. 2016 Jul 19;7:290. doi: 10.3389/fphys.2016.00290. eCollection 2016.

Altered Differential Control of Sympathetic Outflow Following Sedentary Conditions: Role of Subregional Neuroplasticity in the RVLM.

Frontiers in physiology

Madhan Subramanian, Patrick J Mueller

Affiliations

  1. Department of Physiology, Wayne State University School of Medicine Detroit, MI, USA.

PMID: 27486405 PMCID: PMC4949265 DOI: 10.3389/fphys.2016.00290

Abstract

Despite the classically held belief of an "all-or-none" activation of the sympathetic nervous system, differential responses in sympathetic nerve activity (SNA) can occur acutely at varying magnitudes and in opposing directions. Sympathetic nerves also appear to contribute differentially to various disease states including hypertension and heart failure. Previously we have reported that sedentary conditions enhanced responses of splanchnic SNA (SSNA) but not lumbar SNA (LSNA) to activation of the rostral ventrolateral medulla (RVLM) in rats. Bulbospinal RVLM neurons from sedentary rats also exhibit increased dendritic branching in rostral regions of the RVLM. We hypothesized that regionally specific structural neuroplasticity would manifest as enhanced SSNA but not LSNA following activation of the rostral RVLM. To test this hypothesis, groups of physically active (10-12 weeks on running wheels) or sedentary, male Sprague-Dawley rats were instrumented to record mean arterial pressure, LSNA and SSNA under Inactin anesthesia and during microinjections of glutamate (30 nl, 10 mM) into multiple sites within the RVLM. Sedentary conditions enhanced SSNA but not LSNA responses and SSNA responses were enhanced at more central and rostral sites. Results suggest that enhanced SSNA responses in rostral RVLM coincide with enhanced dendritic branching in rostral RVLM observed previously. Identifying structural and functional neuroplasticity in specific populations of RVLM neurons may help identify new treatments for cardiovascular diseases, known to be more prevalent in sedentary individuals.

Keywords: brainstem; physical inactivity; sympathetic nerve activity

References

  1. Brain Res. 1985 Apr 8;331(2):353-7 - PubMed
  2. Hypertension. 2012 Mar;59(3):545-7 - PubMed
  3. Hypertension. 2013 Apr;61(4):806-11 - PubMed
  4. Clin Exp Pharmacol Physiol. 2001 Jan-Feb;28(1-2):115-9 - PubMed
  5. J Auton Nerv Syst. 1992 Jan;37(1):1-10 - PubMed
  6. J Physiol. 1990 Sep;428:371-85 - PubMed
  7. Hypertension. 2010 Mar;55(3):644-51 - PubMed
  8. Neurosci Lett. 1990 Mar 2;110(1-2):91-6 - PubMed
  9. Auton Neurosci. 2009 Jun 15;148(1-2):5-15 - PubMed
  10. Exp Brain Res. 2012 Jul;220(2):121-33 - PubMed
  11. Am J Physiol Regul Integr Comp Physiol. 2009 Sep;297(3):R665-74 - PubMed
  12. Basic Res Cardiol. 2006 May;101(3):223-34 - PubMed
  13. J Physiol. 2009 Dec 1;587(Pt 23):5513 - PubMed
  14. Nat Rev Neurosci. 2006 May;7(5):335-46 - PubMed
  15. Clin Exp Hypertens. 1995 Jan-Feb;17(1-2):209-21 - PubMed
  16. Clin Exp Pharmacol Physiol. 2007 Apr;34(4):377-84 - PubMed
  17. Exp Physiol. 2005 Sep;90(5):673-82 - PubMed
  18. Exp Physiol. 2010 Jan;95(1):34-40 - PubMed
  19. Exp Physiol. 2010 Jan;95(1):61-8 - PubMed
  20. Clin Exp Pharmacol Physiol. 2008 Apr;35(4):508-11 - PubMed
  21. Circ Res. 1989 Apr;64(4):686-94 - PubMed
  22. Am J Physiol. 1991 Apr;260(4 Pt 2):H1072-9 - PubMed
  23. Am J Physiol. 1994 Oct;267(4 Pt 2):R935-44 - PubMed
  24. J Appl Physiol (1985). 2011 Dec;111(6):1854-62 - PubMed
  25. Am J Physiol Heart Circ Physiol. 2015 Jul 15;309(2):H235-43 - PubMed
  26. Am J Physiol. 1994 Oct;267(4 Pt 2):H1549-56 - PubMed
  27. J Comp Neurol. 2004 Nov 15;479(3):257-70 - PubMed
  28. Science. 1995 Oct 27;270(5236):644-6 - PubMed
  29. Hypertens Res. 2000 Nov;23(6):633-41 - PubMed
  30. J Neurosci. 2003 Jun 1;23(11):4657-66 - PubMed
  31. J Am Coll Cardiol. 2009 Jul 28;54(5):375-85 - PubMed
  32. Am J Physiol Regul Integr Comp Physiol. 2010 Jun;298(6):R1468-74 - PubMed
  33. J Appl Physiol (1985). 2007 Feb;102(2):803-13 - PubMed
  34. Ann N Y Acad Sci. 2001 Jun;940:431-43 - PubMed
  35. PLoS One. 2011;6(6):e21141 - PubMed
  36. Acta Physiol Scand. 1992 Mar;144(3):317-23 - PubMed
  37. J Comp Neurol. 2014 Feb 15;522(3):499-513 - PubMed
  38. J Physiol. 1988 Jan;395:41-56 - PubMed
  39. Physiol Rev. 2010 Apr;90(2):513-57 - PubMed
  40. Am J Physiol Regul Integr Comp Physiol. 2011 May;300(5):R1230-40 - PubMed
  41. Braz J Med Biol Res. 2011 Sep;44(9):848-54 - PubMed
  42. Front Physiol. 2012 Nov 26;3:447 - PubMed
  43. Am J Physiol Heart Circ Physiol. 2011 Jul;301(1):H230-40 - PubMed
  44. Am J Physiol Regul Integr Comp Physiol. 2002 Sep;283(3):R604-14 - PubMed
  45. J Auton Nerv Syst. 1997 Dec 3;67(1-2):67-78 - PubMed
  46. J Physiol. 2005 Feb 15;563(Pt 1):249-63 - PubMed

Publication Types

Grant support