Muscle type-specific myosin isoforms in crustacean muscles

LaFramboise, William A.; Griffis, Bruce; Bonner, Philip H.; Warren, Wendy; Scalise, Deborah; Guthrie, Robert D.; Cooper, Robin L.

doi:10.1002/(sici)1097-010x(20000101)286:1<36::aid-jez4>3.0.co;2-g

Cited by 31 publications

(23 citation statements)

References 72 publications

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“…MHCs from different muscle samples were resolved according to the methods of Talmadge and Roy (1993), with the modification that 0.1% β-mercaptoethanol was added to the upper buffer (Blough et al, 1996;LaFramboise, 2000). Samples were separated on 8% resolving gels (50:1 acrylamide:N,N′-methylenebisacrylamide) on 15·cm gels (BioRad Protean II) at 200·V for at least 48·h.…”

Section: Analysis Of Myofibrillar Proteinsmentioning

confidence: 99%

“…S1 fibers have higher myosin ATPase activities than S2 fibers (Mykles, 1988;Neil et al, 1993), which correlates with a twofold higher maximum shortening velocity (Holmes et al, 1999). A recent study of crayfish muscle fiber types identified up to four different MHC proteins (LaFramboise et al, 2000).…”

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confidence: 99%

“…Similarly, Neil et al (1993) demonstrated that the superficial abdominal flexor muscle in the Norway lobster, Nephrops norvegiucus, is comprised of S1 and S2 fibers that form distinct anatomical bundles from the medial to lateral positions. The correlation between muscle phenotype and innervation, combined with the distinct anatomical segregation of muscle types, makes crustacean systems desirable models for studying basic muscle function (LaFramboise et al, 2000).…”

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Analysis of myofibrillar proteins and transcripts in adult skeletal muscles of the American lobsterHomarus americanus: variable expression of myosins, actin and troponins in fast, slow-twitch and slow-tonic fibres

Medler

Mykles

2003

Journal of Experimental Biology

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SUMMARYSkeletal muscles are diverse in their contractile properties, with many of these differences being directly related to the assemblages of myofibrillar isoforms characteristic of different fibers. Crustacean muscles are similar to other muscles in this respect, although the majority of information about differences in muscle organization comes from vertebrate species. In the present study, we examined the correlation between myofibrillar protein isoforms and the patterns of myofibrillar gene expression in fast, slow-phasic(S1) and slow-tonic (S2) fibers of the American lobster Homarus americanus. SDS-PAGE and western blotting were used to identify isoform assemblages of myosin heavy chain (MHC), P75, troponin T(TnT) and troponin I (TnI). RT-PCR was used to monitor expression of fast and slow (S1) MHC, P75 and actin in different fiber types, and the MHC and actin levels were quantified by real-time PCR. Fast and slow fibers from the claw closers predominantly expressed fast and S1 MHC,respectively, but also lower levels of the alternate MHC. By contrast, fast fibers from the deep abdominal muscle expressed fast MHC exclusively. In addition, slow muscles expressed significantly higher levels of actin than fast fibers. A distal bundle of fibers in the cutter claw closer muscle was found to be composed of a mixture of S1 and S2 fibers,many of which possessed a mixture of S1 and S2 MHC isoforms. This pattern supports the idea that S1 and S2fibers represent extremes in a continuum of slow muscle phenotype. Overall,these patterns demonstrate that crustacean skeletal muscles cannot be strictly categorized into discrete fiber types, but a muscle's properties probably represent a point on a continuum of fiber types. This trend may result from differences in innervation pattern, as each muscle is controlled by a unique combination of phasic, tonic or both phasic and tonic motor nerves. In this respect, future studies examining how muscle phenotype correlates with innervation pattern may help account for variation in crustacean fiber types.

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Section: Analysis Of Myofibrillar Proteinsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Analysis of myofibrillar proteins and transcripts in adult skeletal muscles of the American lobsterHomarus americanus: variable expression of myosins, actin and troponins in fast, slow-twitch and slow-tonic fibres

Medler

Mykles

2003

Journal of Experimental Biology

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“…Fur-ther investigations on sensory neurons could relate the mechanisms of neuromodulators to those known at neuromuscular junctions with varying synaptic efficacy Cooper 1995, 1996;LaFramboise et al, 2000). Recently, we have been addressing the influence of these neuromodulators on motor nerve terminals Cooper, 1999, 2000;Griffis et al, 2000;He et al, 1999;Southard et al, 2000) and central integration of sensory input (Strawn et al, 2000).…”

Section: Discussionmentioning

confidence: 99%

The effects of serotonin and ecdysone on primary sensory neurons in crayfish

Cooper¹,

Ward²,

Braxton³

et al. 2003

Microscopy Res & Technique

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The overall behaviors and motivational states observed during social interactions and throughout the molting cycle of crayfish have been linked to the effects of humoral neuromodulators. Both serotonin (5-HT) and a molt-related hormone, 20-hydroxyecdysone (20-HE), are known to be present in the hemolymph of crustaceans. To determine if they alter the activity of a primary sensory neuron that monitors proprioceptive information, we examined their effects on the activity of the slow-adapting muscle receptor organ (MRO) of the crayfish abdomen, a model sensory system that has been extensively studied. 5-HT within the range of 100 nM to 1 M, increases the firing frequency of the neuron during sustained stimulation. In experiments in which 20-HE was added alone, an increase in the firing frequency also occurred, although to a lesser degree than that for 5-HT at the same concentrations. When the MRO is first exposed to 20-HE, followed sequentially by 5-HT, the activity increases to about the same degree as in the reverse order of exposure. This outcome indicates that mixtures of these endogenous neuromodulators, at various levels, are more important in alternating behavior than the absolute level of any one of them introduced alone.

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“…Due to the relative simplicity of crustacean NMJs and the ability to measure pre-and postsynaptic components discretely, the mechanistic actions of neuromodulators on synaptic plasticity can readily be differentiated. Depending on the particular crustacean skeletal muscle, individual muscle fibers may be innervated by a single phasic or single tonic motor neuron or multiples of both types of motor neurons (Atwood, 1973(Atwood, , 1976Cooper, 1995, 1996a,b;LaFramboise et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Intrinsic differences in sensitivity to 5-HT between high- and low-output terminals innervating the same target

Cooper

Dönmezer

Shearer

2003

Neuroscience Research

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The differential action of neuromodulators on synapses of various efficacy provides additional fine tuning of synaptic regulation beyond frequency induced plasticity. We used the well-characterized high-and low-output motor nerve terminals, of the tonic and phasic neuromuscular junctions (NMJs) in the walking leg extensor muscle of the crayfish, to investigate differential actions of serotonin (5-HT) since both terminals innervate the same target. The excitatory postsynaptic potentials of the tonic NMJ are enhanced to a greater extent than for the phasic NMJs during exposure to 5-HT (100 nM). Macropatch current recordings at identified sites along the motor nerve terminals and quantal analysis indicate that mean quantal content is substantially increased by 5-HT. The overall probability of vesicular release increases to a greater extent at tonic terminals than at phasic terminals when exposed to 100 nM 5-HT. Measures in the area (i.e. charge) of spontaneous quantal currents indicate no difference in postsynaptic receptivity to the glutamatergic synaptic transmission upon exposure to 5-HT. The results provide new details concerning differential modulation of low-and high-output synapses present on the same target tissue. #

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Muscle type-specific myosin isoforms in crustacean muscles

Cited by 31 publications

References 72 publications

Analysis of myofibrillar proteins and transcripts in adult skeletal muscles of the American lobsterHomarus americanus: variable expression of myosins, actin and troponins in fast, slow-twitch and slow-tonic fibres

Analysis of myofibrillar proteins and transcripts in adult skeletal muscles of the American lobsterHomarus americanus: variable expression of myosins, actin and troponins in fast, slow-twitch and slow-tonic fibres

The effects of serotonin and ecdysone on primary sensory neurons in crayfish

Intrinsic differences in sensitivity to 5-HT between high- and low-output terminals innervating the same target

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