HISTOCHEMICAL AND MYOSIN COMPOSITION OF VAMPIRE BAT (DESMODUS-ROTUNDUS) PECTORALIS-MUSCLE TARGETS A UNIQUE LOCOMOTORY NICHE

The vampire bat pectoralis muscle contains at least four fiber types d istributed in a nonhomogeneous pattern. One of these fiber types, here termed Ile, can be elucidated only by adenosine triphosphatase (ATPas e) histochemistry combined with reactions against antifast and antislo w myosin antibodies. The histochemical and immunohistochemical observa tions indicate a well-developed specialization of function within spec ific regions of the muscle. In parallel, analyses of native myosin iso forms and myosin heavy chain isoforms indicate two points. First, the histochemical ''type IIe'' fiber is predominant in cranial portions of the muscle, and myosin extracted from these regions exhibits a unique electrophoretic mobility not observed in the myosin isoforms of more traditional laboratory mammals. Second, the type I fibers are confined to the pectoralis abdominalis muscle and a small adjacent region of t he caudal part of the pectoralis. This pattern of type I fiber distrib ution is considered a derived character state compared to muscle histo chemical phenotype and isoform composition in the pectoralis muscles o f other phyllostomids we have studied (Artibeus jamaicensis, Artibeus lituratus, Carollia perspicillata). We relate this to the unique locom otory needs of the common vampire bat, Desmodus rotundus. (C) 1993 Wil ey-Liss, Inc.