Selective effect of sensitization on the phenotype of slow and fast skeletal muscle of guinea pig

Abstract

The use of monoclonal antibodies to the heavy cbains of fast myosin shows that twicerepeated sensitization (ovalburnin + aluminum hydroxide gel) elicits different effects in the muscles examined, raising the content of the fast muscle fibers in m. frenicus and of the slow muscle fibers in m. plantaris. Changes in the irnmunohistochemical profile do not entirely correlate with changes in the contractile characteristics.Key Words: fast and slow muscle; sensitization; immunohistochemistry; myosins; contractile characteristics Humoral regulation of the function of skeletal muscle remains one of the least studied problems. Whereas the effect of some hormones on the morphofunctional characteristics of skeletal muscle has been thoroughly investigated [4,13], the role of other humoral factors in the regulation of skeletal muscle phenotypes has been neglected. It is not yet certain what effect sensitization has on different parameters of skeletal muscle [3,9], although the skeletal muscle tissue could hardly remain insensitive to allergic processes in the organism. The importance of studies of allergic reactions in skeletal muscle is primarily determined by clinical demands. Diverse disturbances of the external respiration, which may derive from altered functions of the diaphragmal and intercostal muscles, due to allergic reaction, are among the factors underlying the pathogenesis of bronchial asthma [5]. The slow and fast muscles of mammals have been shown to differ with respect to their plasticity and may respond differently to the same factors [2,10,11]. We previously demonstrated, using histochemical methods, that sensitization does not alter the The aim of the present study was to investigate the qualitative composition of myosin and the contractile characteristics of the slow and fast skeletal muscle of guinea pig under conditions of protein-induced sensitization. MATERIALS AND METHODSThe experiments were carried out on the fast (m. plantaris) and slow (m. frenicus) muscles of adult male guinea pigs weighing 350-400 g. Twice-repeated sensitization was performed by subcutaneous injections in the thigh of a solution containing 10 lag ovalbumin and 1 mg dry aluminum hydroxide gel in 1 ml of physiological saline per animal. The second injection was performed 14 days after the first. The level of sensitization was monitored by the methods of passive skin anaphylaxis [7] and thin-layer immune assay [8]; on day 21 the antibody (AB) titer constituted 1/256-1/1024 and 1/ 25-1/512, respectively. The muscles were examined 3 weeks after the start of experiments. Animals were decapitated under deep ether anesthesia, the muscles were excised, and cryostate sections 8 I.t

Possible mechanisms of allergic reactions of the skeletal muscle

“…Our results indicate that sensitization changes considerably the contractile parameters of the skeletal muscles (Table 2), which agrees with our previous observation that sensitization affects the myosin spectrum [3,6].…”

“…In experiments with denervation and sensitization, the animals were injected with ovalbumin on day 1 after surgery. The contractile response of the left diaphragmal muscle (m. phrenicus, a 5-mm wide stripe) was studied in vitro in the isometric regime as described previously [6]. The following parameters were measured: latent period, time of the maximum tension development, rate of contraction, force of contraction, half-time of relaxation, and duration of the plateau.…”

Possible Mechanisms for the Effect of Protein Sensitization on Contractile Function of Fast and Slow Muscles in Mice

“…Sensitization-induced changes in muscle fibers probably concern the outer membrane [1], electron-mechanical coupling [3], or contractile protein system [5]. Variations in contractile properties of mouse leg muscles during PS reflect the complexity of changes in SM under conditions of immunobiological reconstruction of the organism.…”

Ovalbumin‐induced sensitization affects non‐quantal acetylcholine release from motor nerve terminals and alters contractility of skeletal muscles in mice

“…All the changes occurring in SM during OS could theoretically affect the plasma membrane, including postjunctional membrane with a high densitiy of nAChRs (Ado et al 1984), electromechanical coupling (Gushchin, 1973) or the system of contractile proteins (Deviataev & Valiullin, 1994). The overwhelming majority (about 90%) of ACh is released from motor nerve terminals of mammals in an NQ form (Malomouzh & Nikol'skii, 2007).…”