Myogenic response of rat femoral small arteries in relation to wall structure and [Ca(2+)](i).
The present study investigated the influence of media thickness on myogenic tone and intracellular calcium concentration ([Ca(2+)](i)) in rat skeletal muscle small arteries. A ligature was loosely tied around one external iliac artery of 5-wk-old spontaneously hypertensive rats. At 18 wk of age, femoral artery blood pressure was 102 +/- 11 mmHg (n = 15) on the ligated side and 164 +/- 6 mmHg (n = 15) on the contralateral side. Small arteries feeding the gracilis muscle had a reduced media cross-sectional area and a reduced media-to-lumen ratio on the ligated side, where also the range of myogenic constriction was shifted to lower pressures. However, when expressed as a function of wall stress, diameter responses were nearly identical. [Ca(2+)](i) was higher in vessels from the ligated hindlimb at pressures above 10 mmHg, but vasoconstriction was not accompanied by changes in [Ca(2+)](i). Thus the myogenic constriction here seems due primarily to changes in intracellular calcium sensitivity, which are determined mainly by the force per cross-sectional area of the wall and therefore altered by changes in vascular structure.
Matchkov
Vladimir V
VV
Department of Physiology, University of Aarhus, DK-8000 Aarhus C, Denmark. vvm@fi.au.dk
Tarasova
Olga S
OS
Mulvany
Michael J
MJ
Nilsson
Holger
H
D000375:Aging / Q000502:physiology; D000818:Animals; D001158:Arteries / Q000187:drug effects / Q000378:metabolism*; D001794:Blood Pressure / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D006614:Hindlimb / Q000098:blood supply*; D007083:Iliac Artery / Q000502:physiology; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000378:metabolism; D008026:Ligation; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D013314:Stress, Mechanical; D017540:Tunica Media / Q000502:physiology*; D014654:Vascular Patency / Q000187:drug effects / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*
D002121:Calcium Channel Blockers; D002118:Calcium