Ca2+ sensitivity of isolated arterioles from the hamster cheek pouch.

When isolated from the hamster cheek pouch, cannulated, and perfused, 60- to 90-μm arterioles spontaneously contracted to 67±4% of maximum diameter. Vessel sensitivity to variations in extracellular Ca 2+ was then evaluated. Tone, regardless of its source, was highly dependent on the concentration of Ca 2+ in the bathing solution