Distribution of Intracarotidly Injected Serotonin in the Brain

¹ From the Thudichum Psychiatric Research Laboratory, Galesburg State Research Hospital, Galesburg, Illinois

Cross circulation experiments, according to the technique of Heymans and Heymans and Swiss and Maison, have been used to study the distribution of serotonin (2–4 mg) injected in the internal carotid artery of the recipient rabbit. Approximately 1% of the injected neurohormone has been recovered from different parts of brain while more than 50% of the injected serotonin is present in the venous jugular blood of the recipient. Some of the injected serotonin reaches the general circulation probably through the sinus vertebralis longitudinalis causing hypotension. Pretreatment with Marsilid does not change the rate of serotonin entrance in nervous tissues although the increase of serotonin content in brain of animals treated with Marsilid is confirmed.