Abstract
It was previously reported (1-3) that the shock-like fall in blood pressure of the cat produced by an intravenous injection of Congo red was partly due to an increase in concentration of serotonin (5-HT) in the blood plasma. It was also noted that congo red caused a reduction in number of blood platelets in the cat both in vitro and in vivo. It was, therefore, suggested that Congo red destroyed platelets to release 5-HT into plasma by an unknown mechanism.
The present work was undertaken with the intent of investigating the mechanism of 5-HT release. In addition, the role of 5-HT released during the colloid shock was investigated, using several colloids including congo red, inulin and mastix.
