Effect of fibrin-fibrinogen degradation products on human basilar artery preparations.

Experiments were performed to determine the effects of fibrin-fibrinogen degradation products on the human basilar artery in vivo. Citrated plasma and streptokinase were incubated at 37 degrees C to produce a preparation of fibrinogen degradation products. Aliquots of the incubate were obtained at 90 minutes, 48 hours, and 1 and 2 weeks after preparation, and were separated into fractions of different molecular weight (MWt), using an ultrafiltration technique. Each fraction was tested at each of the above times for contractile activity and possible interaction with a threshold concentration of 5-hydroxytryptamine (5-HT) on the human basilar artery. Contractile activity was initially confined to the 90-minute aliquot fraction MWt greater than 100,000, but as the incubation proceeded, such activity was also seen in the lower MWt fraction less than 100,000 greater than 10,000 at all time intervals. This activity was never seen in the fraction MWt less than 10,000 at any time. Enhancement of the 5-HT response was initially confined to the higher molecular weight fractions, but after 48-hour incubation all fractions showed this activity. It is suggested that products of fibrin-fibrinogen degradation may be involved directly or indirectly in influencing the pathophysiological mechanism(s) responsible for cerebral arterial spasm following subarachnoid hemorrhage.