Effects of early plasmin digests of fibrinogen on isometric tension development in isolated rings of rat pulmonary artery.
The purpose of the study was to determine the effects of early plasmin-mediated digests of rat fibrinogen on the vascular tone of rat pulmonary artery in order to compare with reported vasoactive effects of high levels of isolated human peptides in various rat vascular beds. Isometric tension was monitored in isolated rings of rat pulmonary artery precontracted with phenylephrine (4 x 10(-8) mol). Fibrinogen degradation products (FgDPs) were produced by digestion of rat fibrinogen with plasmin to 1, 2, 3 and 60 minutes whereupon the digestion was stopped by addition of Trasylol. These FgDPs were added to the tissue bath to achieve final concentrations of 6.7, 13.3, 26.7 and 53.3 micrograms/mL i.e. values similar to those found in vivo during thrombolytic therapy for myocardial infarction. Results were expressed as a percentage of a maximal contraction elicited in each ring in response to phenylephrine (10(-5) M). The early FgDP fractions, at these pathophysiological concentrations, did not induce significant change in isometric tension in the isolated pulmonary arterial rings (P > 0.05, ANOVA).
Boutcher
P A
PA
Department of Physiology, University College, Dublin, Ireland.
Gaffney
P J
PJ
Raut
S
S
O'Regan
R G
RG
McLoughlin
P
P
D000818:Animals; D005338:Fibrin Fibrinogen Degradation Products / Q000494:pharmacology*; D005341:Fibrinolysin; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D010656:Phenylephrine / Q000494:pharmacology; D011651:Pulmonary Artery / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D005338:Fibrin Fibrinogen Degradation Products; D014662:Vasoconstrictor Agents; D010656:Phenylephrine; D005341:Fibrinolysin