Differences in microcirculatory bed arrangement in some skeletal muscles of the rat and golden hamster

The architectural features of the most peripheral parts of the microcirculatory bed were studied in selected skeletal muscles (cremaster, retractor, spinotrapezius, and ventral stripe of spinotrapezius) in rats and golden hamsters ranging in weight between 130 and 330 and 130 and 180 g, respectively. In the cremaster muscle of both species, a very complicated, irregular and heterogenous arrangement of terminal arterioles, as well as of postcapillary and collecting venules was found. In the retractor, the most regular arrangement was along the margins of the middle part of muscle, but an irregular brush-like branching of the terminal arterioles and collecting venules limits the use of these areas. Similarly, in spinotrapezius muscle the most regular vascular architecture, complicated by a different fashion of terminal arterioles and collecting venules, was along the ventral border of muscle. The most regular and simplest vascular arrangement was in the ventral stripe of spinotrapezius of the rat. Therefore, this muscle is recommended as most appropriate for intravital experimental studies of the skeletal muscle microcirculatory bed in all age and weight groups.