EDRF released from microvascular endothelial cells dilates arterioles in vivo.
Microvascular endothelial cells (MECs) from rat epididymal fat pad were isolated and cultured in vitro on Cytodex 3 microcarrier beads. In Krebs-suffused cremaster muscle of pentobarbital-anesthetized rats arteriolar diameters (mean control diam 20.9 +/- 0.9 micron) were measured using image shearing video microscopy. Two lines of suffusate (1.5 ml/min each) were established; one contained a column of microcarrier beads only (no cells in line; NC) the other contained a 1-ml column of MECs grown on beads (through cells; TC). The muscle preparation and the MECs were first treated with indomethacin (Indo; 28 microM). Indo treatment blocked arteriolar dilation to A23187 (1 microM) and arachidonic acid (AA; 0.25 microM) administered into the NC line. A 4.0 +/- 0.6 micron increase in arteriolar diameter was observed, however, when A23187 (but not AA) was infused through the TC line containing Indotreated MECs on beads. The A23187-elicited dilation was abolished by the introduction of NG-monomethyl-L-arginine (L-NMMA; 200 microM) into the TC line. Administration of atropine (2 microM) onto the cremaster muscle via the NC line inhibited the dilations in response to acetylcholine (ACh; 2.7 microM) given through the NC line. Infusion of ACh through the TC line onto the atropine-treated cremaster muscle, however, elicited a 5.8 +/- 1.3 micron increase in arteriolar diameter, a response that was blocked by prior administration of L-NMMA into the TC line. Arteriolar dilation induced by adenosine (0.5 microM) or sodium nitroprusside (0.5 microM) applied via the NC or TC line was unaffected by L-NMMA.(ABSTRACT TRUNCATED AT 250 WORDS)
Koller
A
A
Department of Physiology, New York Medical College, Valhalla 10595.
Seyedi
N
N
Gerritsen
M E
ME
Kaley
G
G
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001160:Arterioles / Q000187:drug effects*; D001285:Atropine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D008833:Microcirculation; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D009569:Nitric Oxide; D000001:Calcimycin; D001285:Atropine; D000109:Acetylcholine; D007213:Indomethacin