PT  - JOURNAL ARTICLE
AU  - Shuhei Murase
AU  - Naoyoshi Sakitani
AU  - Takahiro Maekawa
AU  - Daisuke Yoshino
AU  - Ayumu Konno
AU  - Hirokazu Hirai
AU  - Taku Saito
AU  - Sakae Tanaka
AU  - Keisuke Shinohara
AU  - Takuya Kishi
AU  - Yuki Yoshikawa
AU  - Takamasa Sakai
AU  - Makoto Ayaori
AU  - Hirohiko Inanami
AU  - Koji Tomiyasu
AU  - Toru Ogata
AU  - Atsushi Takashima
AU  - Masahiro Shinohara
AU  - Motoshi Nagao
AU  - Yasuhiro Sawada
TI  - Mechanical impact on the head has an antihypertensive effect
AID  - 10.1101/2020.09.21.305706
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.09.21.305706
4099  - http://biorxiv.org/content/early/2020/09/21/2020.09.21.305706.short
4100  - http://biorxiv.org/content/early/2020/09/21/2020.09.21.305706.full
AB  - Nervous cell functions are known to be physiologically regulated by mechanical factors in the brain. However, it remains unclear whether mechanical interventions can modulate the pathophysiological processes underlying brain-related disorders and modify their consequences. Here we show that passive head motion of hypertensive rats, which reproduces mechanical accelerations generated at their heads during treadmill running at a moderate velocity, decreases the expression of angiotensin II type 1 receptor (AT1R) in astrocytes in their rostral ventrolateral medulla (RVLM). This decrease results in lowering their blood pressure. Passive head motion generates interstitial fluid movement that is estimated to exert shear stress with average magnitude of a few Pa on cells in rats’ brainstem. Fluid shear stress of a relevant magnitude decreases AT1R expression in cultured astrocytes, but not in neuronal cells. Furthermore, in hypertensive rats, inhibition of movement of interstitial fluid by its gelation with reactive polyethylene glycol injected into the RVLM eliminates the ability of passive head motion to decrease their blood pressure and AT1R expression in RVLM astrocytes. Consistent with these results from animal experiments, vertically oscillating chair riding of hypertensive adult humans, which reproduces mechanical accelerations generated at their heads during light jogging or fast walking, lowers their blood pressure. Our findings indicate that moderate mechanical impact on the head has an antihypertensive effect by modulating the function of RVLM astrocytes through interstitial fluid shear stress. We anticipate mechanical regulation to underlie a variety of positive effects of physical exercise on human health, particularly those related to brain functions.Competing Interest StatementThe authors have declared no competing interest.