A chronic intravenous cannulation technique adapted for behavioral studies

A simple inexpensive technique for chronic intravenous cannulation of small laboratory animals is described. With this technique multiple daily blood samples can be taken to form serial hormone profiles of individual animals. The procedure does not interfere with ongoing behavioral and physiological processes. As a measure of stress caused by the procedure, prolactin levels were determined by radioimmunoassay. Prolactin levels were only elevated on the first postoperative day; subsequent levels were comparable to those measured in decapitated animals. It is concluded that this technique can be very useful for short- and long-term experiments in the field of hormones and behavior.