scholarly journals CHOLINESTERASES AND MOTOR END-PLATES IN DEVELOPING DUCK SKELETAL MUSCLE

1965 ◽  
Vol 13 (7) ◽  
pp. 559-565 ◽  
Author(s):  
K. S. KHERA ◽  
Q. N. LAHAM
Keyword(s):  
Skeletal Muscle ◽  
Nerve Fibers ◽  
Diisopropyl Fluorophosphate ◽  
Thigh Muscles ◽  
Motor End Plates ◽  
Subneural Apparatus

End-plates in the thigh muscles of duck embryos were first recognized with myristoylcholine as substrate at the 19th day of incubation. Each appeared as a cholinesterase-positive dot surrounded by a small halo which rapidly increased in size during the 20th and 21st days. The endplates were usually oval in shape, averaging 33 µ x 25 µ with a subneural apparatus 5-12µ wide. The latter contained refringent lamellas arranged transversely in a palisade fashion. From the 21st day to the day of hatching (27-29 days) the number of end-plates progressively increased. After hatching, the myristoylcholine-reacting end-plates were difficult to locate. With acetylthiocholine as substrate, the embryonal end-plates were not demonstrable; however, the posthatched tissues showed numerous end-plates. The nerve trunks and nerve fibers gave a faintly positive myristoylcholine reactions in all stages after the 19th day of incubation. On the basis of the effects of eserine and diisopropyl fluorophosphate, the structures reacting with myristoylcholine and acetylthiocholine contained specific chohinesterase. The end-plates containing nonspecific cholinesterase also appeared on the 19th day of incubation and appeared to increase gradually in number until the 15th postembryonic day; thereafter they seemed to decrease.

scholarly journals Prion Infection of Skeletal Muscle Cells and Papillae in the Tongue

2004 ◽  
Vol 78 (13) ◽  
pp. 6792-6798 ◽  
Author(s):  
Ellyn R. Mulcahy ◽  
Jason C. Bartz ◽  
Anthony E. Kincaid ◽  
Richard A. Bessen
Keyword(s):  
Skeletal Muscle ◽  
Sensory Nerve ◽  
Meat Products ◽  
Muscle Cells ◽  
Nerve Fibers ◽  
Skeletal Muscle Cells ◽  
Lingual Papillae ◽  
Intracerebral Inoculation ◽  
Axon Terminals ◽  
Prion Infection

ABSTRACT The presence of the prion agent in skeletal muscle is thought to be due to the infection of nerve fibers located within the muscle. We report here that the pathological isoform of the prion protein, PrPSc, accumulates within skeletal muscle cells, in addition to axons, in the tongue of hamsters following intralingual and intracerebral inoculation of the HY strain of the transmissible mink encephalopathy agent. Localization of PrPSc to the neuromuscular junction suggests that this synapse is a site for prion agent spread between motor axon terminals and muscle cells. Following intracerebral inoculation, the majority of PrPSc in the tongue was found in the lamina propria, where it was associated with sensory nerve fibers in the core of the lingual papillae. PrPSc staining was also identified in the stratified squamous epithelium of the lingual mucosa. These findings indicate that prion infection of skeletal muscle cells and the epithelial layer in the tongue can be established following the spread of the prion agent from nerve terminals and/or axons that innervate the tongue. Our data suggest that ingestion of meat products containing prion-infected tongue could result in human exposure to the prion agent, while sloughing of prion-infected epithelial cells at the mucosal surface of the tongue could be a mechanism for prion agent shedding and subsequent prion transmission in animals.

ATP concentrations and muscle tension increase linearly with muscle contraction

2003 ◽  
Vol 95 (2) ◽  
pp. 577-583 ◽  
Author(s):  
Jianhua Li ◽  
Nicholas C. King ◽  
Lawrence I. Sinoway
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Contraction ◽  
Motor Nerve ◽  
Muscle Tension ◽  
Nerve Fibers ◽  
Ventral Root ◽  
Ventral Roots ◽  
Root Stimulation ◽  
Stimulation Of

Previous studies have suggested that activation of ATP-sensitive P2X receptors in skeletal muscle play a role in mediating the exercise pressor reflex (Li J and Sinoway LI. Am J Physiol Heart Circ Physiol 283: H2636–H2643, 2002). To determine the role ATP plays in this reflex, it is necessary to examine whether muscle interstitial ATP (ATPi) concentrations rise with muscle contraction. Accordingly, in this study, muscle contraction was evoked by electrical stimulation of the L7 and S1 ventral roots of the spinal cord in 12 decerebrate cats. Muscle ATPi was collected from microdialysis probes inserted in the muscle. ATP concentrations were determined by the HPLC method. Electrical stimulation of the ventral roots at 3 and 5 Hz increased mean arterial pressure by 13 ± 2 and 16 ± 3 mmHg ( P < 0.05), respectively, and it increased ATP concentration in contracting muscle by 150% ( P < 0.05) and 200% ( P < 0.05), respectively. ATP measured in the opposite control limb did not rise with ventral root stimulation. Section of the L7 and S1 dorsal roots did not affect the ATPi seen with 5-Hz ventral root stimulation. Finally, ventral roots stimulation sufficient to drive motor nerve fibers did not increase ATP in previously paralyzed cats. Thus ATPi is not largely released from sympathetic or motor nerves and does not require an intact afferent reflex pathway. We conclude that ATPi is due to the release of ATP from contracting skeletal muscle cells.

Rapid dilation of arterioles with single contraction of hamster skeletal muscle

2006 ◽  
Vol 290 (1) ◽  
pp. H119-H127 ◽  
Author(s):  
Jurgen W. G. E. VanTeeffelen ◽  
Steven S. Segal
Keyword(s):  
Skeletal Muscle ◽  
Muscarinic Receptor ◽  
Muscle Blood Flow ◽  
Rapid Onset ◽  
Receptor Activation ◽  
Retractor Muscle ◽  
Time Integral ◽  
Exercise Onset ◽  
Tension Time ◽  
Motor End Plates

Skeletal muscle blood flow increases rapidly with exercise onset, but little is known of where or how the rapid onset of vasodilation (ROV) is governed within the microcirculation. In the retractor muscle of anesthetized hamsters ( n = 26), we tested the following: 1) where in the resistance network ROV occurred, 2) how microvascular responses were affected by the duration of contraction, and 3) whether ROV involved muscarinic receptor activation. Single tetanic contractions were evoked using supramaximal field stimulation (100 Hz) to depolarize motor end plates. In response to a 200-ms contraction, red blood cell (rbc) velocity ( Vrbc) in feed arteries (FA; rest: 17.8 ± 2 mm/s) increased within 1 s; a transient first peak (P1; 50 ± 7% increase) occurred at ∼5 s; and a second peak (P2; 50 ± 15% increase) occurred at ∼15–20 s. For vasodilation, P1 increased in frequency from proximal FA (2/7) and 1A arterioles (2/7) to distal 2A (4/7) and 3A (7/8) arterioles ( P < 0.05). Relative to resting (and maximal, 10 μM sodium nitroprusside) diameters, P1 increased from proximal (FA, 3 ± 2% from 57 ± 5 μm) to distal (3A, 27 ± 6% from 14 ± 1 μm) vessel branches ( P < 0.05). P2 was manifest in all vessels and increased relative to resting diameters from FA (11 ± 3%) to 3A (36 ± 6%) branches ( P < 0.01). Extending a contraction from 200 to 1,000 ms (tension × time integral from 17 ± 2 to 73 ± 4 mN/mm2 × s) increased P1 and P2 for Vrbc and for diameter ( P < 0.05) while reducing the time of onset for P2 ( P < 0.05). Superfusion with atropine (10 μM) attenuated P1 of vasodilation (200 ms contraction) from 26 ± 8% to 6 ± 2% ( n = 7 across branches; P < 0.05) and reduced the diameter × time integral by 46 ± 13% ( P < 0.05) without changing P2. We conclude that ROV in the hamster retractor muscle is initiated in distal arterioles, increases with the duration of muscle contraction, and involves muscarinic receptor activation.

Morphology of nerve fibers regenerating through freeze-thawed autogenous skeletal muscle grafts in rats

1990 ◽  
Vol 3 (2) ◽  
pp. 107-119 ◽  
Author(s):  
S. E. Gschmeissner ◽  
J. M. Gattuso ◽  
M. A. Glasby
Keyword(s):  
Skeletal Muscle ◽  
Nerve Fibers

scholarly journals Species-specific second antibodies reduce spurious staining in immunocytochemistry.

1984 ◽  
Vol 32 (4) ◽  
pp. 395-402 ◽  
Author(s):  
C R Houser ◽  
R P Barber ◽  
G D Crawford ◽  
D A Matthews ◽  
P E Phelps ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Area Postrema ◽  
Cross Reactivity ◽  
Nerve Fibers ◽  
Primary Antibody ◽  
General Level ◽  
Peripheral Tissues ◽  
Background Staining ◽  
Motor End Plates ◽  
Species Specific

Spurious staining related to the second (linking) antibodies was observed in immunocytochemical specimens processed with an unlabeled antibody method. Some of this staining was suspected to result from species cross-reactivity of the second antibodies with endogenous immunoglobulin Gs in the tissue. Therefore, species-specific second antibodies were obtained, and the staining patterns of tissue processed with such antibodies were compared with those of tissue processed with standard (nonspecies-specific) second antibodies. In these studies, a monoclonal antibody to choline acetyltransferase (ChAT) was utilized as the primary antibody, and a similarly prepared monoclonal antibody that did not react with ChAT served as a control antibody. Spurious staining that included staining of discrete tissue and cellular components as well as amorphous background staining was present in both control and experimental tissue processed with standard second antibodies. Such staining was virtually eliminated in tissue processed with species-specific second antibodies. In specimens from the central nervous system, for example, species-specific second antibodies greatly reduced dark staining within the area postrema, in the pia-arachnoid membranes, and around blood vessels as well as the staining of small dot-like structures within some large neurons. In addition, the general level of background staining was reduced in both adult and developing tissues, thus permitting clearer visualization of many positively stained structures. In peripheral tissues such as skeletal muscle, spurious staining of connective tissue elements was eliminated, allowing the observation of previously occluded ChAT-positive structures such as nerve fibers and motor end-plates. Thus, species-specific second antibodies appear to be very useful for immunocytochemistry, particularly when the primary antibody and the tissue to be studied are from closely related species.

scholarly journals CALCIUM INFLUX IN SKELETAL MUSCLE AT REST, DURING ACTIVITY, AND DURING POTASSIUM CONTRACTURE

1959 ◽  
Vol 42 (4) ◽  
pp. 803-815 ◽  
Author(s):  
C. Paul Bianchi ◽  
A. M. Shanes
Keyword(s):  
Skeletal Muscle ◽  
Rana Pipiens ◽  
Calcium Influx ◽  
Nerve Fibers ◽  
Sartorius Muscle ◽  
Potassium Contracture ◽  
Anion Substitution ◽  
Cent Increase ◽  
Fast Twitch ◽  
Passive Influx

Calcium influx in the sartorius muscle of the frog (Rana pipiens) has been estimated from the rate of entry of Ca45. In the unstimulated preparation it is about equal to what has been reported for squid giant axons, but that per impulse is at least 30 times greater than in nerve fibers. The enhanced twitch when NO-2 replaces Cl- in Ringer's is associated with at least a 60 per cent increase in influx during activity, whereas this anion substitution does not affect the passive influx significantly. Calcium entry during potassium contracture is even more markedly augmented than during electrical stimulation, but only at the beginning of the contracture; thus, when a brief Ca45 exposure precedes excess K+ application, C45 uptake is increased three- to fivefold over the controls not subjected to K+, whereas when C45 and K+ are added together, no measurable increase in Ca45 uptake occurs. These findings are in keeping with the brevity of potassium contracture in "fast (twitch)" fibers such as in sartorius muscle.

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