In in situ rat hearts, left ventricular (LV) volume is measured by our newly developed conductance catheter and simultaneously LV pressure is measured by a thin Millar's catheter inserted from the apex. We obtained a curved LV end-sytolic pressure-volume relation (ESPVR) during an aortic occlusion.　From this curved ESPVR, we calculated a pressure-volume area (a measure of total mechanical energy).　In this experimental system, it becomes possible to investigate LV mechanoenergetics in ejecting hearts under the physiological conditions, i.e., almost intact autonomic nervous control.　

Studies on ESPVR and its characteristcs of rat in situ ejecting hearts.

Effects of somato-autonomic or autonomic-autonomic nerve reflex on cardiac mechanoenergetics in rat in situ ejecting hearts

Effects of a cardiotonic agent (including inodilators) on ESPVR in rat in situ ejecting hearts (Kishi and Nakahashi).

Development of a conductance catheter system for a mouse (Ito and Takaki).

1. Ito H, Takaki M, Yamaguchi H, Tachibana H, Suga H: Left ventricular volumetric conductance catheter for rats. Am J Physiol 270 (Heart Circ Physiol 39): H1509-H1514, 1996.

2. Tachibana H, Takaki M, Lee S, Ito H, Yamaguchi H, Suga H: New mechanoenergetic evaluation of left ventricular contractility in in situ rat hearts. Am J Physiol 272 ( Heart Circ Physiol 41 ) : H2671-2678, 1997.

3. Lee S, Ohga Y, Tachibana H, Syuu Y, Ito H, Harada M, Suga H and Takaki M: Effects of myosin isozyme shift on curvilinearity of the left ventricular end-systolic pressure-volume relation of in situ rat hearts. Jpn J Physiol 48(6), 445-455,1998.

4. Kishi T, Nakahashi K, Ito H, Taniguchi S, Takaki M: Effects of milrinone on left ventricular end-systolic pressure-volume relation of in situ rat hearts. Clin Exp Pharmacol Physiol, 28, 737-742, 2001.

5. Kitagawa Y, Yamashita D, Ito H, Takaki M: The Reversible Effects of Isoproterenol-induced Hypertrophy on in situ Left Ventricular Function in Rat Hearts. Am J Physiol: Heart & Circ Physiol, 287(1) H277-852004.

6. Takeshita D, Shimizu J, Kitagawa Y, Yamashita D, Tohne K, Nakajima-Takenaka C, Ito H, Takaki M: Isoproterenol-induced hypertrophied rat hearts: Does short-term Treatment correspond to long-term treatment? The Journal of Physiological Sciences, 58(3): 179-188, 2008.