[The antithrombotic activity of para-aminobenzoic acid in experimental thrombosis].
It was shown for the first time that p-aminobenzoic acid (PABA), in addition to the previously described fibrinolytic activity, exerts the properties of a direct anticoagulant both in vitro and in vivo. PABA not only displays antithrombin activity, but also inhibits activated factor X and, upon intravenous injection to rats and rabbits, shows the antithrombotic effect. The most pronounced antithrombotic affect was observed at a dose of 1.5 mg/kg. PABA at 0.5 mg/kg has insignificant efficacy and at 3 mg/kg, a high efficacy, but induces hemolysis of erythrocytes in about a half of cases. Equally efficient antithrombotic activity of blood plasma of rats was noted after intravenous injection of low molecular weight heparin "Fraxiparin" at 40 anti-Xa U/kg and PABA at 25 anti-Xa U/kg (1.5 mg/kg). Unlike "Fraxiparin", which exerts an immediate effect, the effect of PABA was expressed within 1.5 to 5 h after injection with a peak of antithrombotic activity at 3 h (which correlates with anti-IIa and anti-Xa activities of plasma) and terminated by 5 h after injection. For PABA, the ratio of anti-Xa to anti-IIa activities (an important parameter, which determines the antithrombotic potential of drugs) equals 2.4. PABA at 0.5 or 1.5 mg/kg did not affect the number of thrombocytes, while at 3 mg/kg, it decreased the number of thrombocytes by 20%. Thus PABA at 1.5 mg/kg, which has a high anticoagulant activity and does not cause side effects, is most interesting for further studies.
Stroeva
O G
OG
Kol'tsov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, Russia.
Akberova
S I
SI
Drozd
N N
NN
Makarov
V A
VA
Miftakhova
N T
NT
Kalugin
S S
SS
D010129:4-Aminobenzoic Acid / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D001777:Blood Coagulation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D005260:Female; D005343:Fibrinolytic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D066298:In Vitro Techniques; D008297:Male; D017762:Nadroparin / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D013927:Thrombosis / Q000097:blood / Q000188:drug therapy*; D013997:Time Factors
D005343:Fibrinolytic Agents; D017762:Nadroparin; D010129:4-Aminobenzoic Acid
Antitromboticheskaia aktivnost' paraaminobenzoĭnoĭ kisloty pri éksperimental'nom tromboze.