Induction of abd-A^{dsRNA.Scer\UAS.cMa}, under the control of the pan-myogenic Scer\GAL4^how-24B (and Scer\GAL80^ts.αTub84B, placed at the restrictive temperature of 29^oC at the onset of metamorphosis) completely prevents terminal chamber differentiation. In particular, the organisation of the myofibrils in segment A5 is unmodified at metamorphosis. The fibrils remain oriented transversally, as in the larval heart, instead of being remodelled and longitudinally oriented. Induction of abd-A^{dsRNA.Scer\UAS.cMa}, under the control of the pan-myogenic Scer\GAL4^how-24B (and Scer\GAL80^ts.αTub84B, placed at the restrictive temperature of 29^oC at the onset of metamorphosis) prevents the formation of nerve terminations, without affecting axon growth. Induction of abd-A^{dsRNA.Scer\UAS.cMa}, under the control of the pan-myogenic Scer\GAL4^how-24B in the cardiac tube does not affect the histolysis of segments A6 and A7, which are eliminated upon abd-A^{dsRNA.Scer\UAS.cMa} induction. Induction of abd-A^{dsRNA.Scer\UAS.cMa}, under the control of either the pan-myogenic Scer\GAL4^how-24B, or the heart-specific Scer\GAL4^NP5169 (both with Scer\GAL80^ts.αTub84B, placed at the restrictive temperature of 29^oC at the onset of metamorphosis), leads to an almost complete transformation of segments A1-A4 into structures characteristic of the terminal chamber. This transformation is characterised by the thinning of the cardiac tube and the longitudinal orientation of the myocyte muscle fibers.