Stretch-dependent calcium uptake associated with myogenic tone in rabbit facial vein.
Many blood vessels possess stretch-dependent myogenic tone. This tone contributes to the active resistance in small arteries, which regulates blood flow in the body. In this report we describe results indicating that stretch-dependent myogenic tone in the rabbit facial vein, a vascular preparation with useful experimental properties, is accompanied by an increased uptake of 45Ca2+. This influx may not occur through voltage-gated Ca2+ channels, since neither the extent of myogenic tone nor 45Ca2+ influx is affected by a concentration of 1,4-dihydropyridine (PN 200-110, 10 nM) that reduces tone and 45Ca2+ influx due to the depolarization by K+. These results indicate that in myogenically active vessels a stretch-activated influx of Ca2+ may occur through distinct Ca2+-entry pathways.
Laher
I
I
University of Vermont, Department of Pharmacology, Burlington 05405.
van Breemen
C
C
Bevan
J A
JA
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D005145:Face / Q000098:blood supply*; D009129:Muscle Tonus / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology; D011817:Rabbits; D013696:Temperature; D014661:Vasoconstriction; D014680:Veins / Q000502:physiology
D011188:Potassium; D002118:Calcium