Poster Title (Current Submission)

A novel technique to study the time course of morphological and functional vascular responses to hypertension in conscious rats

Major(s)

Integrative Physiology

Mentor Name

Dr, Harold Stauss

Mentor Department

Integrative Physiology

Presentation Date

12-3-2009 12:00 AM

Abstract

A novel technique to study the time course of morphological and functional vascular responses to hypertension in conscious rats Harald M. Stauss, Katie M. Leick, Jason W. Burkle, Diane L. Rotella, Kevin R. Rarick, Jonathan D. Alterie, Joshua R. Nelson, Thomas A. Salter, Michael J. Harvey, Sung H. Kim, Thomas Ebnet, Michael G. Anderson* Departments of Integrative Physiology and Molecular Physiology & Biophysics*, The University of Iowa, Iowa City, IA Assessment of morphological vascular responses to exposure to cardiovascular risk factors in experimental animals requires ex vivo experiments that do not allow assessment of the time course of vascular alterations in individual subjects. We used a slit-lamp biomicroscope (resolution < 1 >μm) to photograph the long posterior ciliary artery (LPCA) of the iris in conscious normotensive Wistar Kyoto rats (WKY, n=10) and spontaneously hypertensive rats (SHR, n=10) on regular-salt diet (RS) and in SHR (n=10) on high-salt diet (HS). The same segment along the LPCA was imaged in consecutive weekly imaging sessions and an imaging software was used to determine the wall to lumen (W/L) ratio. After 4 weeks systolic blood pressure (SBP) did not change in WKY (115±5 vs. 111±5 mmHg) and SHR-RS (148±7 vs. 155±3 mmHg) but increased significantly in SHR-RS (139±5 mmHg vs. 166±6 mmHg, p< 0.05). The time course of the changes in W/L ratio of the LPCA mirrored the time course of the SBP changes. While W/L ratio did not change in WKY-RS (+12±10%) and SHR-RS (+18±17%), there was a 39±14% increase in W/L ratio in SHR-HS. Since the LPCA was not dilated pharmacologically the W/L ratio assessed in this study may reflect the combination of morphologic alterations and changes in vascular tone. In vivo imaging of the LPCA may allow assessment of the time course of morphological and functional vascular responses to hypertension in conscious rats.

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Dec 3rd, 12:00 AM

A novel technique to study the time course of morphological and functional vascular responses to hypertension in conscious rats

A novel technique to study the time course of morphological and functional vascular responses to hypertension in conscious rats Harald M. Stauss, Katie M. Leick, Jason W. Burkle, Diane L. Rotella, Kevin R. Rarick, Jonathan D. Alterie, Joshua R. Nelson, Thomas A. Salter, Michael J. Harvey, Sung H. Kim, Thomas Ebnet, Michael G. Anderson* Departments of Integrative Physiology and Molecular Physiology & Biophysics*, The University of Iowa, Iowa City, IA Assessment of morphological vascular responses to exposure to cardiovascular risk factors in experimental animals requires ex vivo experiments that do not allow assessment of the time course of vascular alterations in individual subjects. We used a slit-lamp biomicroscope (resolution < 1 >μm) to photograph the long posterior ciliary artery (LPCA) of the iris in conscious normotensive Wistar Kyoto rats (WKY, n=10) and spontaneously hypertensive rats (SHR, n=10) on regular-salt diet (RS) and in SHR (n=10) on high-salt diet (HS). The same segment along the LPCA was imaged in consecutive weekly imaging sessions and an imaging software was used to determine the wall to lumen (W/L) ratio. After 4 weeks systolic blood pressure (SBP) did not change in WKY (115±5 vs. 111±5 mmHg) and SHR-RS (148±7 vs. 155±3 mmHg) but increased significantly in SHR-RS (139±5 mmHg vs. 166±6 mmHg, p< 0.05). The time course of the changes in W/L ratio of the LPCA mirrored the time course of the SBP changes. While W/L ratio did not change in WKY-RS (+12±10%) and SHR-RS (+18±17%), there was a 39±14% increase in W/L ratio in SHR-HS. Since the LPCA was not dilated pharmacologically the W/L ratio assessed in this study may reflect the combination of morphologic alterations and changes in vascular tone. In vivo imaging of the LPCA may allow assessment of the time course of morphological and functional vascular responses to hypertension in conscious rats.