Blood sampling technique for measurement of plasma arginine vasopressin concentration in conscious and unrestrained rats.

: A new technique for collecting blood from conscious and unrestrained rats is reported. Plasma arginine vasopressin (AVP) concentration has been known to be influenced by various procedures used for blood collection (e.g., manual contact and anesthesia). In the study reported here, the improvement of the routine jugular vein cannula method was undertaken by extending the connection tubing to allow use of a swivel mechanism. Plasma AVP, glucose, and corticosterone concentrations in virgin rats were measured in blood samples collected by use of the new method and of two generally accepted methods (decapitation and routine jugular vein cannula methods). All values of the three parameters obtained were the lowest when the new method was used, suggesting that this new swivel method induced the least stress in the rats.