Somatic muscle

Holden-Dye, L., Brownlee, D.J.A. and Walker, R.J. (1997) The effects of the peptide KPNFIRFamide (PF4) on the somatic muscle cells of the parasitic nematode Ascaris suum. British Journal of Pharmacology 120, 379—386. 

Ascaris somatic muscle cells also possess inhibitory synaptic and extra-synaptic GABA-gated Cl channels (Martin, 1980). Activation of these... 

Martin, R.J. (1982) Electrophysiological effects of piperazine and diethylcarba-mazine on Ascaris suum somatic muscle. British Journal of Pharmacology 77, 255-265. 

The cyclophyllidean oncosphere is well supplied with musculature and the general pattern of muscles appears to be similar in most species. So in both Hymenolepis citelli (which penetrates an invertebrate gut) and E. granulosus (which penetrates a vertebrate gut) there are 16 somatic muscle cells (146, 839). However, E. granulosus has 16 hook muscle cells but H. citelli has only 13. In E. granulosus, the hook muscles have been shown to insert at the collar and base of the hooks and at the basal lamina of the embryonic epithelium. Each pair of hooks has three muscle systems associated with it (a) a protractor system, for hook extensions (b) an abductor system, which draws the hooks together and (c) a retractor system which pulls the hooks into the body (839). 

Nicotinic acetylcholine receptors (uAChRs) are ligand-gated ion channels, and one of the best-studied of the ionotropic receptors. They are found in both the CNS and the peripheral nervous system, as well as in the neuromuscular junctions of somatic muscles. 

In addition, SchistoFLRFamide had an effect upon the locust extensor-tibiae muscle preparation (somatic muscle). Low concentrations (.01 nM-10 nM) produced a potentiation of the amplitude of slow motor neuron induced twitch tension while higher concentrations (100 nM-1000 nM) produced a variable biphasic response with an amplitude of contraction decrease followed by an increase (25). 

Excessive nicotinic cholinergic tone in the somatic muscle groups following OP chemical threat agent exposure causes stimulation of muscle flbers and muscle groups that can lead to fasciculations, twitches, fatigue, and paralysis, depending upon the... 

A. tinman, a Homeobox Gene Required for the Formation of Visceral Musculature, Dorsal Somatic Muscles, and the Heart... 

Figure 2. The function of tinman in the formation of mesodermal tissues. The (eft column shows wild-type embryos and the right column tinman mutant embryos of the same stage and stained with the same markers. (A, B) Neither cardioblasts nor pericardial cells are formed in tin mutants (embryos stained as in Figure 1 ). (C, D) The midgut musculature (stained for flCal expression from an enhancer trap insertion is completely m ssing in tinman mutants. (E, F Dorsal muscles (stained for [iCa expression from a .cZ reporter insertion Yin and Frasch, 1998) are not properly specified in tinman mutants. (G, H) Earlv stage 12. The muscle founders of the S59 cluster I (as detected with an S59 antibody), which give rise to muscles 5 and 25, are not specified in tinman mutants. By contrast, the founder cells of S59 cluster II are formed normally and will develop into muscles 26, 2(r, and 29, (I, J) Stage 11. huttonlesi niRN.A expression in the DM cell precursors (arrow) is absent in tin mutants and DM cells are not formed. (The bilateral pairs of nuclei are Eve-stained neuronal precursors).. Abbreviations DM dorsal median cell precursors dsm dorsal somatic muscles mgv m midgut visceral mesoderm pc pericardial precursors.

B. The Founder Cell Concept of Somatic Muscle Development... 

Gajewski, K., Kim, Y., Choi, C. Y, and Schulz, R. A. (1998). Combinatorial control of Drosophila mef2 gene expression in cardiac and somatic muscle cell linet es. Dev. Genes Evol. 208 382-392. Gajewski, K., Kim, Y., Lee, Y., Olson, E., and Schulz, R. (1997). D-mefi is a target for Tinman activation during Drosophila heart development. EMBO J. 16 515-522. 

Keller, C., Erickson, M., and Abmayr, S. (1997). Misexpression of nautilus induces myogenesis in cardioblasts and alters the pattern of somatic muscle fibers. Dev. Biol. 787 197-212. 

Lin, S., Lin, M., Horvath, P., Reddy, K., and Storti, R. (1997). PDPl, a novel Drosophila PAR domain bZlP transcription factor expressed in developing mesoderm, endoderm and ectoderm, is a transcriptional regulator of somatic muscle genes. Development 724 4685-4696. 

Shishido, E., Ono, N., Kojima, T., and Saigo, K. (1997). Requirements of DFRl/Heartless, a mesoderm-specific Drosophila FGF-receptor. for the formation of heart, visceral and somatic muscles, and ensheathing of longitudinal axon tracts in CNS. Development 724 2119-2128. 

The inner surface of the tegumental syncytium is bounded by a fibrillar basal lamellum. This syncytium, like that of trematodes, is elaborated by cell bodies (subtegumental cells, cytons) that lie beneath the basal lamellum. To the fribrillar components of the basal lamellum are anchored the somatic muscle cells, so that contraction is coupled to movement of the body. Our analysis of the cestode surface focuses on the material bounded by the basal lamellum and the glycocalyx. 

Control of internal Cl levels appears to play an important role in maintaining the membrane potential of the somatic muscle cells, which are much more permeable to Cl than to other ions. A large CC channel that can also conduct organic acids has been described in A. suum muscle membranes (128) the same channel has been found to be expressed on both the inward and outward facing membranes of the hypodermis (K. L. Blair et al., unpublished results). It is not known if this channel plays a role in organic acid excretion across the cuticle (129,130). In vertebrates, muscle membrane potential is dependent primarily on K. ... 

Anatomical results obtained with the positive antisera were helpful in making a decision on which of the neuropeptides to attempt to purify from A. suum. FMRFamide-immunoreactivity occurs in neurons that innervate somatic muscles. These results suggested that putative FMRFamide-like peptides might be involved in motor control. 

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