Contact Info:Email: xuhui2@msu.edu Phone: 517-353-6609 Fax:

Left video (one dimensioon) and right video (three dimensions) show local intracellular calcium transients (calcium sparks) in myocytes from rat mesenteric arteries.  Image was taken by confocol microscopy in collaboration with Dr. Mark Nelson's lab, University of Vermont. See videos one & two on Youtube

 

 

 

Research Synopsis:
My researches include basic cardiovascular physiology, particularly the role of autonomic nervous system and neural-hormonal controlling of blood pressure; and also molecular signaling and receptors/iron channel interaction in vasculature, and how these facts contribute to regulation of vascular tone and blood pressure. My research is highly integrative as studies will be performed in whole animals (in rats and mice) in vivo, at the integrative tissue level and at the molecular level where activity of individual iron channels will be studied.  My recent studies are focused on the role of potassium channel function in regulation of vascular tone in hypertension. Techniques used include:

1)  Integrated cardiovascular function in vivo animal by measurements of blood pressure, heart rate, and renal sympathetic nerve activity;  measurements of small mesenteric arterial and venous contractile and relaxation reactive in ex-vivo; and measurements of smooth muscle membrane potential using intracellular recording in ex vivo. 

2) Pharmacological studies of arterial and venous functions in vitro using pressurized myograph.

3) Molecular biological approaches to analyze the vascular structures, expression and interaction of receptors, iron channels, and intracellular signal conductors in arteries and veins.

4)  Iron channel functions are determined in myocytes from arteries and veins and in transent and stably transfected HEK cells.  Approaches include whole cell, cell atached and inside out signal channel patches; recording of spontaneous outward currents and Ca2+ sparks.

Honors/Awards:
American Heart Association Postdoctoral Fellowship – 2003-2005
Young Scientist Travel Award Recipient for the Experimental Biology Meeting 2004,
New Investigator Travel Award for the Jackson Cardiovascular-Renal Meeting, 2008

Selected Samples Publications:
Xu H, Fink GD, Galligan JJ: ET-1 induced elevations in blood pressure are independent of increases in sympathetic nerve activity in normotensive rats. FASEB J. 15(4): A230, 2001.

Xu H, Fink GD, Chen A, Watts SW, Galligan JJ: Nitric oxide-independent effects of tempol on sympathetic nerve activity and blood pressure in normotensive rats. Hypertension 38(3): P114, p. 510, 2001.

Xu H, Fink GD, Chen A, Watts SW, Galligan JJ: Nitric oxide-independent effects of tempol on sympathetic nerve activity and blood pressure in normotensive rats. Amer. J. Physiol. 281(2): H975-H980, 2001.

Xu H, Fink GD, Galligan JJ: Endothelin-1-induced elevation in blood pressure is independent of increases in sympathetic nerve activity in normotensive rats. J. Cardiovasc. Pharmacol. 38(5): 784-795, 2001.

Xu H, Fink GD, Watts SW, Chen A, Rech R, Galligan JJ: Nitric oxide-dependent and –independent effects of tempol on renal sympathetic nerve activity and blood pressure in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Soc. Neurosci. 27: A242.9, 2001.

Xu H, Fink GD, Galligan JJ: Nitric oxide-dependent and –independent effects of tempol on renal sympathetic nerve activity an blood pressure in deoxycorticosterone acetate (DOCA)-hypertensive rats. Amer. J. Physiol. 283(3): H885-H892, 2002.

Li L, Xu H, Watts SW, Galligan JJ, Fink GD, Chen AF: ET-1 augments venous contractility via NADPH oxidase-induced superoxide in DOCA-salt hypertension. FASEB J. 16(5 Pt 2): p. 1135, 2002.

Fink GD, Watts SW, Chen A, Xu H, Galligan JJ: Superoxide anion contributes to hypertension during inhibition of nitric oxide synthesis. Hypertension 40(3): A7, p. 380, 2002.

Fink GD, Xu H, Galligan JJ: a1-Adrenergic receptors contribute to norepinephrine-induced increases in heart rate in mice. Hypertension 40(3): P65, p. 406, 2002.

Xu H, Fink GD, Galligan JJ: Intra-duodenal administration of tempol lowers blood pressure and inhibits sympathetic nerve activity normotensive and DOCA-salt hypertensive rats. FASEB J. 17(4 Pt 1): #576.5, p. A886, 2003.

Xu H, Fink GD, Galligan JJ: Superoxide independent effects of tempol on blood pressure and sympathetic nerve activity in DOCA-salt hypertensive rats. Hypertension, A57, 2003.

Xu H, Fink GD, Galligan JJ: Tempol lowers blood pressure and sympathetic nerve activity but not vascular O2- in DOCA-salt rats. Hypertension 43(2): 329-334, 2004.

Xu H, Fink GD, Galligan JJ: Increased sympathetic venoconstriction and reactivity to norepinephrine in mesenteric veins in anesthetized DOCA-salt hypertensive rats. Hypertension 44: P48, 2004.

Xu H, Watts SW, Rondelli CM, Fink GD, Galligan JJ. Tempol activates BK channels to cause mesenteric arterial vasodilation in normotensive and deoxycorticosterone acetate (DOCA)-salt hypertensive rats. FASEB J. 19:(4pt1) (Abstract), A703.10, 2005.

Wang H, Xu H, Fink GD, Galligan JJ. Decreased distensibility and myogenic tone in mesenteric veins from DOCA-salt hypertensive rats. Hypertension, 46: (P131)

Taylor M, Xu H, Watts SW, Galligan JJ. Contribution of L-type Ca2+ channels to KCl-induced constriction of mesenteric arteries and veins from normotensive and DOCA-salt hypertensive rats. Hypertension, 46: 10 (P117)

Xu H, Bian X, Watts SW, Hlavacova A, Fink GD, Galligan JJ. Activation of vascular BK channels by tempol in DOCA-salt hypertensive rats. Hypertension, 46: 10 (P121)

Xu H, Bian X, Watts SW, Hlavacova A. Activation of Vascular BK Channel by Tempol in DOCA-salt Hypertensive Rats. Hypertension, 46:1154-1162, 2005.

Xu H, Bian X, Watts SW, Hlavacova A. Activation of vascular BK channel in DOCA-salt hypertension. Hypertension 44: 1154 ­ 1162, 2005.

Xu H, Wang H, Fink GD, Galligan JJ. Contribution of L-type Ca2+ channels to constriction of mesenteric arteries and veins in DOCA-salt hypertensive rats. FASEB A, 890, 2006

Xu H, Jackson WF, Fink GD, Galligan JJ. Activation of potassium channels by tempol in arterial smooth muscle cells from normotensive and DOCA-salt hypertensive rats. Hypertension 48: 1080-1087, 2006.

Xu H, Fink GD, Galligan JJ. Increased sympathetic venoconstriction and reactivity to norepinephrine in mesenteric veins in anesthetized DOCA-salt hypertensive rats. Am J Physiol 293:H160-168, 2007.

Xu H, Wang H, Fink GD, Galligan JJ.  ETA receptor and NADPH oxidase activation impairs vascular BK channel function in DOCA-salt hypertension. FASEB A, 2007
           
Xu H, Fink GD, Galligan JJ.  Impaired venous b-adrenergic receptor dilator function in DOCA-salt      hypertension.  Hypertension 49 (P120), 2007.
           
Szasz T, Eddy S, Xu H, Linder AE, Ni W, Thompson JM, Galligan JJ, et al:  Whole Genome expression profiling of arteries and veins in normotensive and DOCA-salt hypertensive rats.  Hypertension 50: (e77), 2007
           
Xu H, Galligan JJ.  Impaired arterial and venous b-adrenergic receptor dilator function in DOCA-salt hypertension.  FASEB A, 2008.
           
Hlavacova A, Xu H, Galligan JJ.  Differential Ca2+ coupling of alpha-adrenoreceptors in murine mesenteric arteries and veins. FASEB A, 2008.

Xu H, Wang H, Watts SW, Fink GD, Galligan JJ:  Reverse remodeling in mesenteric veins from DOCA-salt hypertensive rats - adaptive response to increased venomotor tone. 62th High blood pressure research conference, 2008

Xu H. BK channel function, venous tone and blood pressure regulation. Jackson Cardiovascular-renal Meeting, 2008