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Invest Ophthalmol Vis Sci. 2000 Jun;41(7):1871-5.

Pressure-induced myogenic responses in isolated bovine retinal arteries.

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  • 1Department of Physiology and Pathophysiology, Ghent University, Belgium.



To investigate whether a pressure-induced myogenic vasoconstriction can be demonstrated in isolated bovine retinal arteries and to determine the cellular mechanisms involved.


Isolated bovine retinal arteries were mounted on a pressure myograph without flow and exposed to stepwise increases in intraluminal pressure. Changes in internal diameter were monitored continuously using an inverted microscope video system.


Bovine retinal arteries showed myogenic tone at pressures higher than 10 mm Hg. This pressure-induced contraction was absent in calcium-free Krebs-Ringer bicarbonate solution. Inhibition of L-type voltage-operated calcium channels with nifedipine (1 microM) suppressed the myogenic contraction. After depolarization of the vascular smooth muscle cells with a K+ 120 mM solution, a pressure-induced contraction was still observed, indicating that besides stimulation of voltage-operated calcium channels, depolarization-independent mechanisms contribute to the pressure-induced myogenic vasoconstriction.


Isolated bovine retinal arteries spontaneously contract when exposed to raised intraluminal pressure. This response depends on extracellular calcium and is blocked by nifedipine. In addition, depolarization-independent mechanisms seem to be involved.

[PubMed - indexed for MEDLINE]
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