Movement-response system for conducting tests on freely-moving animals

Abstract

A movement-responsive system for conducting tests on freely-moving animals is disclosed. The invention includes a container for housing the animal, a mechanism for rotating the container in response to rotational movement of the animal, and one or more test leads connected to the animal for performance of biomedical tests such as infusion, in vivo ultrafiltration, laser-doppler monitoring of blood flow, electrical stimulation and in vivo microdialysis, and a method for automated micro sampling of body fluids in free-moving animals. Because the cage is rotated in response to the animal's rotational movement, no swivel connectors are needed. A rotational sensor assembly is provided to detect rotational movement of the animal within the container. A vertical sensor assembly is mounted to the counterbalanced arm for monitoring vertical movements of the animal. The outputs of the sensor assemblies are routed to a computer or other device for monitoring and/or analyzing the activity of the animal. The container is configured to act as an operant chamber or a metabolic chamber by locating a hole in the bottom of the container and through the rotating mechanism. The invention also enables a new method for sampling body fluids of the animal without restricting the animal's movements. The sampling method uses a syringe pump to result in high fidelity fluid control greatly increasing repeatability of experiments. Further, the method employs pinch valves to control fluid flow in conjunction with an anticoagulant coated tubing, thereby resulting in a blood sampling method that does not require the use of heparinized sterile saline solution as a wash fluid.