Capillaries and arterioles are electrically coupled in hamster cheek pouch

Duling. Capillaries and arterioles are electrically coupled in hamster cheek pouch. Am. J. Physiol. 275 (Heart Circ. Physiol. 44): H1489–H1496, 1998.—In this report we demon-strate electrical communication in the microcirculation be-tween arterioles and capillary networks in situ. Microvessel networks in the hamster cheek pouch, which included capillar-ies and their feeding arterioles, were labeled with the voltage-sensitive dye di-8-ANEPPS by intraluminal perfusion through a micropipette. Pulses of 140 mM potassium solution were applied by pressure ejection from micropipettes positioned on arterioles several hundred micrometers upstream from capil-laries. Potassium caused membrane potential changes of 3–11 mV in capillary segments up to 1,200 µm distal to the stimulation site, with time delays of,1 s. Capillary mem-brane potential changes were biphasic, with initial depolariza