Some observations on the efferent innervation of rat soleus muscle spindles

1978 ◽  
Vol 31 (3) ◽  
Author(s):  
B.L. Andrew ◽  
G.C. Leslie ◽  
N.J. Part
Keyword(s):  
Soleus Muscle ◽  
Muscle Spindles ◽  
Efferent Innervation ◽  
Rat Soleus Muscle

scholarly journals Expression of Myosin Heavy Chain Isoforms Along Intrafusal Fibers of Rat Soleus Muscle Spindles After 14 Days of Hindlimb Unloading

2002 ◽  
Vol 50 (11) ◽  
pp. 1543-1553 ◽  
Author(s):  
L. De-Doncker ◽  
F. Picquet ◽  
G. Butler Browne ◽  
M. Falempin
Keyword(s):  
Soleus Muscle ◽  
Muscle Spindles ◽  
Myosin Heavy Chain Isoforms ◽  
Hindlimb Unloading ◽  
Cross Sectional ◽  
Intrafusal Fibers ◽  
Significant Difference ◽  
Slow Type ◽  
Rat Soleus Muscle

Morphological, contractile, histochemical, and electrophoretical characteristics of slow postural muscles are altered after hindlimb unloading (HU). However, very few data on intrafusal fibers (IFs) are available. Our aim was to determine the effects of 14 days of hindlimb unloading on the morphological and immunohistochemical characteristics of IF in rat soleus muscle. Thirty-three control and 32 unloaded spindles were analyzed. The number and distribution of muscle spindles did not appear to be affected after unloading. There was no significant difference in number, cross-sectional area, and histochemical properties of IF between the two groups. However, after unloading, a significant decrease in slow type 1 MHC isoform and a slight increase in slow-tonic MHC expression were observed in the B and C regions of the bag1 fibers. The α-cardiac MHC expression was significantly decreased along the entire length of the bag2 fibers and in the B and C regions of the bag1 fibers. In 12 muscle spindles, the chain fibers expressed the slow type 1 and α-cardiac MHC isoforms over a short distance of the A region, although these isoforms are not normally expressed. The most striking finding of the study was the relative resistance of muscle spindles to perturbation induced by HU.

Characterization of Spindle Afferents in Rat Soleus Muscle Using Ramp-and-Hold and Sinusoidal Stretches

2003 ◽  
Vol 89 (1) ◽  
pp. 442-449 ◽  
Author(s):  
Laurent De-Doncker ◽  
Florence Picquet ◽  
Julien Petit ◽  
Maurice Falempin
Keyword(s):  
Conduction Velocity ◽  
Soleus Muscle ◽  
Muscle Length ◽  
Muscle Spindles ◽  
Linear Range ◽  
Fiber Types ◽  
First Response ◽  
Rat Soleus Muscle ◽  
The Right ◽  
Response Group

The discharge properties of 51 afferents were studied in the rat soleus muscle spindles. Under deep anesthesia using a pentobarbital sodium solution (30 mg/kg), a laminectomy was performed and the right L4 and L5 dorsal and ventral roots were transected near their entry into the spinal cord. In situ, the minimal ( L min) muscle length [3 ± 0.08 (SE) cm] of the soleus was measured at full ankle extension. Unitary potentials from the L5dorsal root were recorded in response to ramp-and-hold stretches applied at 3 mm (S3) and 4 mm (S4) amplitudes and four stretch velocities (6, 10, 15, and 30 mm/s), sinusoidal stretches performed at four amplitudes (0.12, 0.25, 0.5, and 1 mm) and six stretch frequencies (0.5, 1, 2, 3, 6, and 10 Hz), and vibrations applied at 50-, 100-, and 150-Hz frequencies. These two kinds of stretches were performed at three different muscle lengths ( L min+10%, L min+15%, and L min+20%), whereas vibrations were applied at L min+20% muscle length. Conduction velocity of the fibers was calculated but did not allow to discriminate different fiber types. However, the mean conduction velocity of the first fiber group (43.3 ± 0.8 m/s) was significantly higher than that of the second fiber group (33.9 ± 0.9 m/s). Three parameters allowed to differentiate the responses of primary and secondary endings: the dynamic index (DI), the discharge during the stretch release from the ramp-and-hold stretches, and the linear range and the vibration sensitivity from sinusoidal stretches. The slope histogram of the linear regression based on the DI and the stretch velocity was clearly bimodal. Therefore the responses were separated into two groups. During the stretch release at a velocity of 3 mm/s, the first response group ( n = 26) exhibited a pause, whereas the second ( n = 25) did not. The linear range of the second ending group (0.12–1 mm) was broader than that of the first (0.12–0.25 mm). The first ending group showed a higher sensitivity to high-vibration frequencies of small amplitude than the second. In comparison with the literature, we can assert that the first and the second ending groups corresponded to the primary and secondary endings, respectively. In conclusion, our study showed that in rat soleus muscle spindles, it was possible to immediately classify the discharge of Ia and II fibers by using some parameters measured under ramp-and-hold and sinusoidal stretches.

Effects of Hypodynamia-Hypokinesia on the Muscle Spindle Discharges of Rat Soleus Muscle

2003 ◽  
Vol 89 (6) ◽  
pp. 3000-3007 ◽  
Author(s):  
Laurent De-Doncker ◽  
Florence Picquet ◽  
Julien Petit ◽  
Maurice Falempin
Keyword(s):  
Soleus Muscle ◽  
Dorsal Root ◽  
Weight Bearing ◽  
Muscle Spindles ◽  
Linear Range ◽  
Fiber Types ◽  
Vibration Sensitivity ◽  
Afferent Fibers ◽  
Rat Soleus Muscle ◽  
Static Sensitivity

The aim of this study was to determine whether Ia and II fiber discharges of soleus muscle spindles were modified after a 14-day period of hypodynamia (absence of weight bearing) and hypokinesia (reduction of motor activity). Fifty-one and 38 afferent fibers were studied, respectively, in control and hypodynamia-hypokinesia (HH) groups. Under deep anesthesia (pentobarbital, 30 mg/kg), a L3–L6 laminectomy was performed. Unitary potentials from the L5 dorsal root were recorded in response to ramp-and-hold stretches applied at two stretch amplitudes (3 and 4 mm) and four stretch velocities (6, 10, 15, and 30 mm/s) and to sinusoidal stretches applied at four stretch amplitudes (0.12, 0.25, 0.5, and 1 mm) and six stretch frequencies (0.5, 1, 2, 3, 6, and 10 Hz). In both animal groups, the Ia fibers showed higher dynamic index values, smaller linear range, and higher vibration sensitivity than the II fibers. They also exhibited a pause in their discharges during the stretch release contrary to II fibers, which displayed no pause in their responses. After HH, our results showed that for both fiber types all parameters measured under ramp-and-hold stretches (except the static sensitivity) were significantly increased and under sinusoidal stretches, the vibration sensitivity increased, and the response amplitude only increased at 0.12-mm stretch amplitude. The linear range of Ia afferents was limited to 0.12 mm, whereas it was unchanged for the II fibers. After HH, the stretches could be better transmitted to the muscle spindles, probably resulting from changes in passive mechanical properties of the soleus.

In vitro autoregulation of glucose utilization in rat soleus muscle

Diabetes ◽  
1987 ◽  
Vol 36 (9) ◽  
pp. 1041-1046 ◽  
Author(s):  
S. Sasson ◽  
D. Edelson ◽  
E. Cerasi
Keyword(s):  
Soleus Muscle ◽  
Glucose Utilization ◽  
Rat Soleus Muscle
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