Vasoconstrictor responses to polymorphonuclear leucocytes from atherosclerotic rabbits.
1. The vascular contractile effects of polymorphonuclear leucocytes (PMN) isolated from control rabbits and from rabbits made atherosclerotic by 1% cholesterol feeding for 8 weeks were examined. 2. Rings of control rabbit thoracic aorta with or without endothelium were mounted at 2 g tension in 10 mL organ baths and were submaximally contracted by phenylephrine (0.1 mumol/L). After 30 min incubation at 37 degrees C, the supernatant of PMN (5 x 10(7)/mL, in Tyrode solution containing 0.25% bovine serum albumin) was obtained by centrifugation for addition to the vascular preparation. 3. Control PMN supernatant (443 microL) caused contraction (0.58 +/- 0.15 g, n = 11) of phenylephrine-contracted aortic rings, which was prevented by removal of the endothelium (0.11 +/- 0.07 g, n = 5, P < 0.05). However, the control PMN supernatant had no contractile effect on aortic rings at resting tension (0.00 +/- 0.00 g, n = 8). 4. By comparison, atherosclerotic PMN supernatant (443 microL) caused a significantly greater contraction of the aortic rings (1.41 +/- 0.13 g, n = 9, P < 0.05 vs control PMN supernatant) that was only partly inhibited by removal of the endothelium (0.45 +/- 0.20 g, n = 9, P < 0.05). Moreover, PMN supernatants from four of seven atherosclerotic rabbits contracted aortic rings at resting tension (3.5 +/- 1.4 g, n = 7). 5. These results suggest that the release of a stable vasoconstrictor substance(s) by PMN is enhanced under conditions of atherosclerosis.(ABSTRACT TRUNCATED AT 250 WORDS)
Department of Pharmacology, University of Melbourne, Parkville, Victoria, Australia.
C G
CG
Sobey
J L
JL
Hart
O L
OL
Woodman
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000473:pathology / Q000503:physiopathology; D001161:Arteriosclerosis / Q000097:blood*; D004036:Diet, Atherogenic; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009504:Neutrophils / Q000502:physiology*; D010656:Phenylephrine / Q000494:pharmacology; D011817:Rabbits; D014661:Vasoconstriction / Q000502:physiology*
D010656:Phenylephrine; D000109:Acetylcholine