The unanesthetized instrumented animal preparation.

The use of the unanesthetized instrumented animal preparation in exercise training studies is discussed. The advantages and disadvantages of this preparation are given. Several examples of the type of data that can be collected using this preparation are cited and a scheme is proposed to aid in the understanding of the mechanisms underlying the cardiac adaptation to exercise training. One example given was the response to the infusion of isoproterenol before and during training. The results clearly demonstrate an increased responsiveness to the beta-receptor agonist. Another example was the change in coronary flow with atrial pacing and the use of this relationship as an index of a changed coronary vascular bed. Some future direction for research efforts are discussed with the main thrust being the role of the autonomic nervous system in the mechanism of training.