Function and cytochemical characteristics of postural limb muscles of the rhesus monkey: A telemetered EMG and immunofluorescence study

Using telemetered electromyography and immunocytochemical fibre typing (of both fresh frozen and preserved specimens), the present paper demonstrates clearly that at the elbow, knee, and ankle joints, the rhesus monkey (Macac a mulatta) is endowed with one extensor-muscle head specialized for posture . These postural heads are distinguished by (a) recruitment at low levels t o maintain joint position against the effect of gravity, (b) recruitment ne ar maximum levels during walking, and (c) high content and relatively large size of slow, fatigue-resistant (type 1) muscle fibres, The nonpostural he ads of the investigated muscles were recruited at levels correlated to the strenuousness of the effort and are notable by the small percentage a nd si ze of slow muscle fibres. The postmortem stability of the structural proper ties of myosin makes immunocytochemical fibre typing suitable for the study of preserved cadavers. Copyright (C) 1999 S. Karger AG, Basel.