R represents the emission fluorescence ratio of fura-2 from excitation at 340 and 380nm. The GHS-R1a antagonists, [D-Lys3]-GHRP-6 (GHRP6, 200 nM) and BIM28163 (BIM,100 nM), completely blocked the effects of 1 nM hexarelin (H) and 10 nM ghrelin (G) post-treatment (post) on sarcomere shortening (A) and [Ca2+]i transients (B). These peptides alone did not produce any noticeable change in sarcomere shortening (A) and [Ca2+]i transients (B). For sarcomere shortening experiments, n = 99, 84, 52, 95, 46,100, 50 and 61 in control, ischemic, GHRP6, G post, G post +GHRP6, BIM, H post and H post+BIM groups, respectively. For [Ca2+]i transient experiments, n = 72, 80, 55, 103, 69, 60, 66 and 68 in control, ischemic, GHRP6, G post, G post +GHRP6, BIM, H post and H post+BIM groups, respectively. Data were analyzed by one-way ANOVA with Tukey's post hoc test, and expressed as means ± S.E.M. *P < 0.05, ** P < 0.01, *** P < 0.001.