scholarly journals THE MODULATORY EFFECTS OF SEROTONIN, NEUROPEPTIDE F1 AND PROCTOLIN ON THE RECEPTOR MUSCLES OF THE LOBSTER ABDOMINAL STRETCH RECEPTOR AND THEIR EXOSKELETAL MUSCLE HOMOLOGUES

1993 ◽  
Vol 174 (1) ◽  
pp. 363-374
Author(s):  
V. M. Pasztor ◽  
L. B. Golas
Keyword(s):  
Muscle Fibres ◽  
Sensory Afferents ◽  
Tension Development ◽  
Sensory Neurones ◽  
Multiple Loci ◽  
Receptor Organ ◽  
Two Measures ◽  
Low Incidence ◽  
Passive Stretch ◽  
Receptor Muscle

The muscle receptor organ (MRO) of the lobster is a complex proprioceptive system lying in parallel with the axial extensor musculature. Two peripherally located sensory neurones extend stretch-sensitive dendrites into individual receptor muscle strands one tonic (RM1) and one phasic (RM2). Previous studies have shown that the sensitivity of the sensory neurones to passive stretch could be enhanced by serotonin and proctolin. Here we show that the receptor muscles and their exoskeletal muscle homologues are also responsive to serotonin, proctolin and, in addition, to neuropeptide F1 (TNRNFLRF-NH2). Two measures of motor performance were enhanced by all three neurohormones: EJP amplitude and nerve-evoked tension development. Serotonin was the most effective modulator of both tonic and phasic muscles. F1 had powerful effects on the phasic extensor muscle. A low incidence of tonic muscle fibres with synapses responding to the neurohormones suggests that there are distinct populations of synapses: those sensitive to specific modulators and others that are insensitive. These findings, taken together with the enhancing effects of modulation on the primary sensory afferents, suggest that circulating neurohormones may act at multiple loci in the MRO system in a concerted and hormone-specific manner to alter the flow of proprioceptive feedback.

scholarly journals On inhibition as a reflex accompaniment of the tendon jerk and of other forms of active muscular response

1928 ◽  
Vol 103 (725) ◽  
pp. 321-336 ◽  
Keyword(s):  
Tonic Contraction ◽  
Muscle Fibres ◽  
Action Current ◽  
Decerebrate Rigidity ◽  
Extensor Muscles ◽  
Receptor Organ ◽  
Passive Stretch ◽  
In Virtue Of ◽  
Tendon Jerk ◽  
Constant Interval

In the condition of decerebrate rigidity the extensor muscles involved are in a state of tonic contraction, which is accompanied by a series of small action-currents, first demonstrated by Dusser de Barenne (9) and Buytendijk (4). Fulton and Pi-Suñer (12) have recently observed that these action-currents cease during the course of a tendon jerk in the same muscle, and that their reappearance precedes by a constant interval, and therefore is almost certainly the action-current accompaniment of the small mechanical contraction which is usually seen delaying the decline of the decerebrate tendon jerk. This mechanical contraction on the decline of the tendon jerk was known to earlier workers (24) as the tonic after-discharge of the jerk, and was described as the "hump" or "myotatic appendage" of the jerk, by Ballif, Fulton and Liddell (2). It was interpreter by them as a reflex contraction caused by the sudden relaxation of the jerk, a phenomenon of stretch-reflex type caused by the passive lenghening of the muscle during the relaxation. Fulton and Pi-Suñer (12) interpret the absence of action-currents during the jerk as the result of slackening of some receptor organ in the muscle by the mechanical shortening taking place during the tendon jerk, and their reappearance as due to the reflex result of renewal of tension upon that receptor. This receptor, which, ex hypothesi , must react to passive stretch by causing reflex excitation in the same muscle, these latter authors identified with the muscle spindle, since in their opinion that organ, in virtue of lying "in parallel" with the muscle fibres, was likely to be slackened when the muscle substance surrounding it contracted.

Coxal Muscle Receptors in the Crab: The Receptor Potentials of S and T Fibres in Response to Ramp Stretches

1971 ◽  
Vol 55 (3) ◽  
pp. 813-832
Author(s):  
B. M. H. BUSH ◽  
ALAN ROBERTS
Keyword(s):  
Motor Nerve ◽  
Large Diameter ◽  
Muscle Fibres ◽  
Dynamic Component ◽  
Static Responses ◽  
Basal Joint ◽  
Muscle Receptors ◽  
Shore Crabs ◽  
Static Nature ◽  
Receptor Muscle

1. Intracellular and extracellular recordings from the two large-diameter S and T sensory fibres of the posterior thoracico-coxal muscle receptor in shore crabs confirm the graded, dynamic-static nature of the receptor potentials evoked by stretching the receptor muscle, and the lack of afferent impulses. 2. Slow ramp-function stretches evoke receptor potentials with characteristic shapes, which differ between the two fibres in several respects: (i) The dynamic component in the S fibre resembles an algebraic sum of length and velocity responses and a variable initial ‘acceleration’ (?) transient, while in the T fibre it commonly declines (‘adapts’) during stretching, especially at greater velocities and starting lengths. (ii) On release of stretch the S fibre usually exhibits a ‘negative velocity response’, but the T fibre repolarizes rapidly often with a slight hyperpolarization. (iii) The dynamic response of the T fibre is generally greater than that of the S fibre, and increases more steeply and approximately logarithmically with stretch velocity over a 10- to 50-fold range. (iv) The ‘static response’ or degree of depolarization increases fairly linearly with receptor length in the S fibre but very non-linearly in the T fibre. (v) The T fibre displays pronounced hysteresis in its dynamic and static responses at increasing and decreasing lengths, but the S fibre shows little hysteresis. (vi) The T fibre but not the S fibre commonly shows small rapid oscillations or ‘noise’ superimposed upon strongly depolarized ‘static’ potentials. (vii) The S and T responses may be affected reciprocally by some forms of receptor muscle contraction. 3. Graded receptor potentials evoked in the ‘D’ fibre by stretching the non-muscular depressor-receptor strand of the coxo-basal joint show little hysteresis. 4. Receptor muscle fibres respond to motor nerve stimulation or spontaneous motor impulses from the thoracic ganglion with slow, facilitating and summating excitatory junctional potentials. 5. The mechanisms underlying the differences between S and T responses, and their functional significance to the animal, are discussed, and comparisons are drawn with other muscle receptors.

The Effects of Acclimation Temperature on a Neuromuscular System of the Crayfish, Astacus Leptodactylus

1979 ◽  
Vol 78 (1) ◽  
pp. 281-293
Author(s):  
MIKKO HARRI ◽  
ERNST FLOREY
Keyword(s):  
Membrane Lipids ◽  
Characteristic Temperature ◽  
Resting Membrane Potential ◽  
Acclimation Temperature ◽  
Muscle Fibres ◽  
Astacus Leptodactylus ◽  
Tension Development ◽  
Temperature Range ◽  
Wide Range ◽  
Warm Acclimation

1. Crayfish, Astacus leptodactylus, were acclimated to 12 °C and to 25 °C. Nerve muscle preparations (closer muscle of walking legs) were subjected to temperatures ranging from 6 to 32 °C. 2. The resting membrane potential of muscle fibres was found to increase with temperature in a linear manner, but with a change in slope at around 170 in cold-acclimated preparations, and around 24 °C in warm-acclimated ones. 3. Temperature acclimation shifted the temperature range of maximal amplitudes of fast and slow e.j.p.s toward the acclimation temperature. Optimal facilitation of slow e.j.p.s also occurred near the respective acclimation temperature. 4. E.j.p. decay time is nearly independent of temperature in the upper temperature range but increases steeply when the temperature falls below a critical range around 17 °C in preparations from cold-acclimated animals, and around 22 °C after acclimation to 25 °C. 5. Peak depolarizations reached by summating facilitated e.j.p.s are conspicuously independent of temperature over a wide range (slow and fast e.j.p.s of cold-acclimated preparations, fast e.j.p.s of warm-acclimated ones) which extends to higher temperatures after warm acclimation in the case of fast e.j.p.s. In warm-acclimated preparations the peak depolarization of slow e.j.p.s first falls then rises and falls again as the temperature increases from 8 to 32 °C. 6. Tension development elicited by stimulation of the slow axon at a given frequency reaches maximal values at the lower end of the temperature range in cold-acclimated preparations. The maximum is shifted towards 20 °C after warm acclimation. Fast contractions decline with temperature; possible acclimation effects are masked by the great lability of fast contractions in warm-acclimated preparations. 7. It is suggested that changes in the composition of membrane lipids may be responsible for the effects of acclimation on the electrical parameters and their characteristic temperature dependence.

Control of tension development in scallop muscle fibres with foreign regulatory light chains

Nature ◽  
1980 ◽  
Vol 286 (5773) ◽  
pp. 626-628 ◽  
Author(s):  
R. M. Simmons ◽  
A. G. Szent-Györgyi
Keyword(s):  
Light Chains ◽  
Muscle Fibres ◽  
Tension Development ◽  
Regulatory Light Chains

Local anaesthetics inhibit tension development and Nile blue fluorescence signals in frog muscle fibres

Nature ◽  
1979 ◽  
Vol 277 (5695) ◽  
pp. 400-402 ◽  
Author(s):  
CARLO CAPUTO ◽  
JULIO VERGARA ◽  
FRANCISCO BEZANILLA
Keyword(s):  
Nile Blue ◽  
Local Anaesthetics ◽  
Frog Muscle ◽  
Muscle Fibres ◽  
Blue Fluorescence ◽  
Tension Development

scholarly journals Functional organisation of anterior thoracic stretch receptors in the deep-sea isopod Bathynomus doederleini: behavioural, morphological and physiological studies

2001 ◽  
Vol 204 (20) ◽  
pp. 3411-3423 ◽  
Author(s):  
Masazumi Iwasaki ◽  
Ayako Ohata ◽  
Yoshinori Okada ◽  
Hideo Sekiguchi ◽  
Akiyoshi Niida
Keyword(s):  
Deep Sea ◽  
Dynamic Range ◽  
Adaptive Behaviour ◽  
Cell Type ◽  
Segmental Mobility ◽  
Tonic Response ◽  
Single Receptor ◽  
Stretch Receptors ◽  
Receptor Organ ◽  
Receptor Muscle

SUMMARY The relationship between segmental mobility and the organisation of thoracic stretch receptors was examined in the deep-sea isopod Bathynomus doederleini, which shows a developed adaptive behaviour during digging. The movements of segments during digging were analysed from video recordings, which showed that a large excursion occurred in the anterior thoracic segments. Dye-fills of axons revealed four types of thoracic stretch receptor (TSR): an N-cell type (TSR-1), a differentiated N-cell type (TSR-2), a muscle receptor organ (MRO)-type with a long, single receptor muscle (TSR-3) and an MRO-type with a short, single receptor muscle (TSR-4 to TSR-7). Physiologically, TSR-1 and TSR-2 are tonic-type stretch receptors. TSR-3 to TSR-7 show two kinds of stretch-activated responses, a tonic response and a phasico-tonic response in which responses are maintained as long as the stretch stimulus is delivered. Both TSR-2, with a long muscle strand, and TSR-3, with a single, long receptor muscle, have a wide dynamic range in their stretch-activated response. In addition, TSR-2 is controlled by an intersegmental inhibitory reflex from TSR-3. These results suggest that, although TSR-1 has no receptor muscle and TSR-2 has a less-differentiated receptor-like muscle, they are fully functional position detectors of segmental movements, as are the MRO-type receptors TSR-3 to TSR-7.

Cellular insertion of primary and secondary myotubes in embryonic rat muscles

Development ◽  
1989 ◽  
Vol 107 (2) ◽  
pp. 243-251
Author(s):  
M.J. Duxson ◽  
Y. Usson
Keyword(s):  
Ultrastructural Study ◽  
Muscle Tension ◽  
Electrical Coupling ◽  
Muscle Fibres ◽  
Tension Development ◽  
End To End ◽  
Developing Muscle ◽  
Two Populations ◽  
Unique Relationship ◽  
Adhering Junctions

Mammalian muscles develop from two populations of myotubes; primary myotubes appear first and are few in number; secondary myotubes appear later and form most of the muscle fibres. We have made an ultrastructural study to investigate how primary and secondary myotubes in embryonic rat muscles transmit tension during the period of their development. Primary myotubes extend from end to end of the muscle from the earliest times, and attach directly to the tendon. In contrast, newly formed secondary myotubes are short cells which insert solely into the primary myotubes by a series of complex interdigitating folds along which adhering junctions occur. As the secondary myotubes lengthen and mature, their insertion is progressively transferred from the primary myotube to the tendon proper. We suggest that this variable insertion of immature secondary myotubes, combined with complex patterns of innervation and electrical coupling in developing muscle, makes it difficult to predict the overall contribution of secondary myotubes to muscle tension development. This work extends other studies showing the unique relationship between a primary myotube and its associated secondary myotubes, indicating that these may constitute a developmental compartment.

Physiological features of the opercularis muscle and their effects on vibration sensitivity in the bullfrog Rana catesbeiana

1987 ◽  
Vol 131 (1) ◽  
pp. 189-204
Author(s):  
T. E. Hetherington
Keyword(s):  
Inner Ear ◽  
Slow Rate ◽  
Rana Catesbeiana ◽  
Muscle Tension ◽  
Isometric Tension ◽  
Sensory Function ◽  
Morphological Evidence ◽  
Muscle Fibres ◽  
Ground Vibrations ◽  
Tension Development

The amphibian opercularis muscle connects a movable otic element (the operculum) to the pectoral girdle and can act in reception of ground vibrations. Various physiological parameters of the opercularis muscle of the bullfrog Rana catesbeiana were measured and compared with similar measurements on the iliofibularis muscle of the hindlimb. The opercularis muscle is a very slowly contracting muscle, with a Vmax of 1.81 muscle lengths s-1 compared to a Vmax of 6.24 muscle lengths s-1 for the iliofibularis muscle. The opercularis muscle develops tension slowly, taking about 10 s to attain maximum isometric tension when stimulated at 100 Hz. The muscle can retain high levels of tension for several minutes, and following stimulation has a time to half-relaxation of about 4–6 s. The slow velocity of contraction, slow rate of tension development, fatigue-resistance and slow rate of relaxation of the opercularis muscle support morphological evidence that it consists mostly of tonic muscle fibres. Experiments were also made to examine the effects of muscle tension on reception of ground vibrations as measured by inner ear microphonics. Severing the nerve supplying the opercularis muscle produced slight decreases of no more than 2 dB in responses to vibrations from 25 to 200 Hz. Artificial stimulation of the opercularis muscle after severing the nerve supplying the muscle increased responses to vibration across the entire frequency range. Higher tension levels produced greater increases in responses; at the highest tensions used (about 120 kN m-2) responses were increased by as much as 4.5 dB. The opercularis muscle is therefore specialized for slow but prolonged contractions, and tension is important in its sensory function. A tensed opercularis muscle appears to transmit faithfully motion of the forelimb, produced by vibrations, to the operculum such that the latter moves relative to the inner ear fluids.

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