Imperial College London
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ProfessorDarrylOverby

Faculty of Engineering, Department of Bioengineering

Professor of Mechanobiology
 
 
 
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Contact

 

+44 (0)20 7594 6376d.overby

 
 
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Location

 

3.07Bessemer BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Madekurozwa:2021:10.1152/ajpcell.00473.2020,
author = {Madekurozwa, M and Stamer, WD and Reina-Torres, E and Sherwood, JM and Overby, DR},
doi = {10.1152/ajpcell.00473.2020},
journal = {Am J Physiol Cell Physiol},
pages = {C652--C665},
title = {The ocular pulse decreases aqueous humor outflow resistance by stimulating nitric oxide production.},
url = {http://dx.doi.org/10.1152/ajpcell.00473.2020},
volume = {320},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Intraocular pressure (IOP) is not static, but rather oscillates by 2-3 mmHg because of cardiac pulsations in ocular blood volume known as the ocular pulse. The ocular pulse induces pulsatile shear stress in Schlemm's canal (SC). We hypothesize that the ocular pulse modulates outflow facility by stimulating shear-induced nitric oxide (NO) production by SC cells. We confirmed that living mice exhibit an ocular pulse with a peak-to-peak (pk-pk) amplitude of 0.5 mmHg under anesthesia. Using iPerfusion, we measured outflow facility (flow/pressure) during alternating periods of steady or pulsatile IOP in both eyes of 16 cadaveric C57BL/6J mice (13-14 weeks). Eyes were retained in situ, with an applied mean pressure of 8 mmHg and 1.0 mmHg pk-pk pressure amplitude at 10 Hz to mimic the murine heart rate. One eye of each cadaver was perfused with 100 µM L-NAME to inhibit NO synthase, whereas the contralateral eye was perfused with vehicle. During the pulsatile period in the vehicle-treated eye, outflow facility increased by 16 [12, 20] % (P < 0.001) relative to the facility measured during the preceding and subsequent steady periods. This effect was partly inhibited by L-NAME, where pressure pulsations increased outflow facility by 8% [4, 12] (P < 0.001). Thus, the ocular pulse causes an immediate increase in outflow facility in mice, with roughly one-half of the facility increase attributable to NO production. These studies reveal a dynamic component to outflow function that responds instantly to the ocular pulse and may be important for outflow regulation and IOP homeostasis.
AU  - Madekurozwa,M
AU  - Stamer,WD
AU  - Reina-Torres,E
AU  - Sherwood,JM
AU  - Overby,DR
DO  - 10.1152/ajpcell.00473.2020
EP  - 665
PY  - 2021///
SP  - 652
TI  - The ocular pulse decreases aqueous humor outflow resistance by stimulating nitric oxide production.
T2  - Am J Physiol Cell Physiol
UR  - http://dx.doi.org/10.1152/ajpcell.00473.2020
UR  - https://www.ncbi.nlm.nih.gov/pubmed/33439773
VL  - 320
ER  -
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