Effects of spaceflight on postnatal development of arterial baroreceptor reflex in rats

Authors: Waki, H.1; Katahira, K.2; Yamasaki, M.1; Nagayama, T.1; Katsuda, S.1; Wago, H.1; Okouchi, T.1; O-Ishi, H.3; Miyake, M.4; Miyamoto, Y.5; Shimizu, T.1

Source: Acta Physiologica, Volume 184, Number 1, May 2005 , pp. 17-26(10)

Publisher: Wiley-Blackwell

Buy & download fulltext article:

The full text article is not available.


Abstract Aim: 

It has been reported that spaceflight attenuates the arterial baroreceptor reflex. As this reflex function changes dramatically during postnatal development, we hypothesized that space flight depresses the developmental changes of the reflex system. To test this hypothesis, we evaluated the baroreceptor reflex function in rats, which were exposed to a microgravity environment on a space shuttle 9–25 days after birth. Methods: 

Baroreceptor reflex sensitivity and the afferent sensitivity were evaluated by measuring heart rate (HR) and aortic nerve activity (ANA) changes in response to an increase in mean arterial pressure (MBP) derived by phenylephrine injection (20–50 g kg−1) under urethane-anaesthesia. Results: 

Baroreceptor reflex sensitivity (% change of HR/% change of MBP) was lower in the flight group (FLT: −0.19 ± 0.04, n = 4) than either the asynchronous ground control group (AGC: −0.47 ± 0.06, n = 6, P < 0.01) or the vivarium group (VIV: −0.41 ± 0.07, n = 6, P < 0.05). This was similar to the differences of the afferent sensitivity (% change of ANA/% change of MBP) between FLT (2.07 ± 0.30) and the control groups (AGC: 2.71 ± 0.22, n.s.; VIV: 3.00 ± 0.32, P < 0.05). At the end of 30 days of recovery under normal gravity conditions, however, there were no significant group differences in these parameters. Conclusion: 

These results suggest that the space environment attenuates the postnatal development of the arterial baroreceptor reflex function in rats, which may be partially because of a depression of the postnatal development of the baroreceptor afferents. These functional alterations, however, recover to their normal level on re-exposure to the Earth's gravity.

Keywords: Sprague–Dawley rat; aortic nerve; baroreflex; blood pressure; postnatal development; weightlessness

Document Type: Research Article

DOI: http://dx.doi.org/10.1111/j.1365-201X.2005.01419.x

Affiliations: 1:  Department of Physiology, Fukushima Medical University School of Medicine, Fukushima, Japan 2:  Experimental Animal Center, Fukushima Medical University School of Medicine, Fukushima, Japan 3:  National Space Development Agency of Japan, Tsukuba, Ibaraki, Japan 4:  Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo, Japan 5:  Department of Anesthesiology, The University of Tokyo, Bunkyo-ku, Tokyo, Japan

Publication date: May 1, 2005

Related content



Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content

Text size:

A | A | A | A
Share this item with others: These icons link to social bookmarking sites where readers can share and discover new web pages. print icon Print this page