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Cardiovascular changes of conscious rats after simulated microgravity with and without daily +Gx gravitation

Cardiovascular changes of conscious rats after simulated microgravity with and without daily +Gx gravitation
Cardiovascular changes of conscious rats after simulated microgravity with and without daily +Gx gravitation
This study was designed to test the hypothesis that postsuspension cardiovascular manifestation in conscious rats after a medium-term (28-day) tail suspension (SUS) is hypertensive and tachycardiac and can be prevented by a countermeasure of daily 1-h dorsoventral (-G(x)) gravitation provided by standing (STD).

To assess associated changes in cardiovascular regulation, blood pressure (BP) and heart rate (HR) variability were analyzed by spectral analysis computed by parametric autoregressive (AR) method and by nonlinear recurrence quantification analysis (RQA) and approximate entropy (ApEn) measure.

The results showed that conscious SUS rats manifested hypertensive and tachycardiac response before and after being released from suspension compared with the controls, and the countermeasure of 1 h/day -G(x) prevented the hypertensive response.

Auto- and cross-spectral analysis and transfer function analysis did not show significant changes in cardiovascular variability. However, SUS decreased the three RQA indexes [recurrence percentage (RC%), determinism percentage (DT%), and the longest diagonal line (L(max))] of systolic BP, whereas STD alleviated these changes.

ApEn values of HR data sets were significantly higher in the SUS and SUS + STD groups compared with those of the control group before and after release from suspension. The present study has demonstrated that daily -G(x) for as short as 1 h is sufficient to prevent postsuspension cardiovascular alteration in conscious rats after a medium-term SUS. Nonlinear measures, but not spectral analysis, might provide promising data to estimate the overall changes in cardiovascular autonomic regulation due to microgravity exposure.
8750-7587
1134-1145
Zhang, L. F.
b47ee8d5-cf1f-49ff-90b0-636f68d51b84
Cheng, J. H.
5572e226-f776-4d63-8579-2ebbe270a672
Liu, X.
878efcac-76c6-4ca0-8f4a-425f1e9abdac
Wang, S.
a2223997-9f42-425b-b0c6-1bcb64d9b8fc
Liu, Y.
3f739949-66b7-4396-945b-3e46ae1bd8ba
Lu, H. B.
dbfa7132-892d-4a57-ab2c-07d969ab8d11
Ma, J.
88d926c1-5a55-402e-bd0e-aaa4d3a461a9
Zhang, L. F.
b47ee8d5-cf1f-49ff-90b0-636f68d51b84
Cheng, J. H.
5572e226-f776-4d63-8579-2ebbe270a672
Liu, X.
878efcac-76c6-4ca0-8f4a-425f1e9abdac
Wang, S.
a2223997-9f42-425b-b0c6-1bcb64d9b8fc
Liu, Y.
3f739949-66b7-4396-945b-3e46ae1bd8ba
Lu, H. B.
dbfa7132-892d-4a57-ab2c-07d969ab8d11
Ma, J.
88d926c1-5a55-402e-bd0e-aaa4d3a461a9

Zhang, L. F., Cheng, J. H., Liu, X., Wang, S., Liu, Y., Lu, H. B. and Ma, J. (2008) Cardiovascular changes of conscious rats after simulated microgravity with and without daily +Gx gravitation. Journal of Applied Physiology, 105 (4), 1134-1145. (doi:10.1152/japplphysiol.00184.2008).

Record type: Article

Abstract

This study was designed to test the hypothesis that postsuspension cardiovascular manifestation in conscious rats after a medium-term (28-day) tail suspension (SUS) is hypertensive and tachycardiac and can be prevented by a countermeasure of daily 1-h dorsoventral (-G(x)) gravitation provided by standing (STD).

To assess associated changes in cardiovascular regulation, blood pressure (BP) and heart rate (HR) variability were analyzed by spectral analysis computed by parametric autoregressive (AR) method and by nonlinear recurrence quantification analysis (RQA) and approximate entropy (ApEn) measure.

The results showed that conscious SUS rats manifested hypertensive and tachycardiac response before and after being released from suspension compared with the controls, and the countermeasure of 1 h/day -G(x) prevented the hypertensive response.

Auto- and cross-spectral analysis and transfer function analysis did not show significant changes in cardiovascular variability. However, SUS decreased the three RQA indexes [recurrence percentage (RC%), determinism percentage (DT%), and the longest diagonal line (L(max))] of systolic BP, whereas STD alleviated these changes.

ApEn values of HR data sets were significantly higher in the SUS and SUS + STD groups compared with those of the control group before and after release from suspension. The present study has demonstrated that daily -G(x) for as short as 1 h is sufficient to prevent postsuspension cardiovascular alteration in conscious rats after a medium-term SUS. Nonlinear measures, but not spectral analysis, might provide promising data to estimate the overall changes in cardiovascular autonomic regulation due to microgravity exposure.

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More information

Published date: October 2008
Organisations: Human Sciences Group

Identifiers

Local EPrints ID: 79204
URI: https://eprints.soton.ac.uk/id/eprint/79204
ISSN: 8750-7587
PURE UUID: 636b1f2e-8d23-4f5f-a9f4-a63a50f4b4f6

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Date deposited: 15 Mar 2010
Last modified: 17 Jul 2019 00:12

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