scholarly journals REPETITIVE EXCITATION OF MOTONEURONS BY AFFERENT SHOCK STIMULUS TO MUSCLE NERVE IN THE PREVIOUSLY SPINALIZED CATS

1959 ◽  
Vol 9 (4) ◽  
pp. 498-505 ◽  
Author(s):  
TADAAKI SUMI
Keyword(s):  
Author(s):  
T. E. Hutchinson ◽  
D. E. Johnson ◽  
A. C. Lee ◽  
E. Y. Wang

Microprobe analysis of biological tissue is now in the end phase of transition from instrumental and technique development to applications pertinent to questions of physiological relevance. The promise,implicit in early investigative efforts, is being fulfilled to an extent much greater than many had predicted. It would thus seem appropriate to briefly report studies exemplifying this, ∿. In general, the distributions of ions in tissue in a preselected physiological state produced by variations in the external environment is of importance in elucidating the mechanisms of exchange and regulation of these ions.


1991 ◽  
Vol 39 (12) ◽  
pp. 1617-1625 ◽  
Author(s):  
M J Szabolcs ◽  
A Windisch ◽  
R Koller ◽  
M Pensch

We developed a method for detecting activity of axonal cholinesterase (CE) and carbonic anhydrase (CA)--markers for motor and sensory nerve fibers (NFs)--in the same histological section. To reach this goal, cross-sections of muscle nerves were sequentially incubated with the standard protocols for CE and CA histochemistry. A modified incubation medium was used for CA in which Co++ is replaced by Ni++. This avoids interference of the two histochemical reactions because Co++ binds unspecifically to the brown copper-ferroferricyanide complex representing CE activity, whereas Ni++ does not. Cross-sections of the trapezius muscle nerve containing efferent and afferent NFs in segregated fascicles showed that CE activity was confined to motor NFs. Axonal CA was detected solely in sensory NFs. The number of labeled motor and sensory NFs determined in serial cross-sections stained with either the new or the conventional technique was not significantly different. Morphometric analysis revealed that small unreactive NFs (diameter less than 5 microns) are afferent, medium-sized ones (5 microns less than d less than 7 microns) are unclassifiable, and large ones (d greater than 7 microns) are efferent. The heterogenous CE activity of thick (alpha) motor NFs is linked to the type of their motor units. "Fast" motor units contain CE reactive NFs; "slow" ones have CE negative neurites.


The early development of the head and pharynx of Hynobius nebulosus (11.5 to 32 mm long) and retardatus (27 and 37 mm specimens) was investigated in some detail from transverse serial microtome sections. Analysis included the chondrocranium, jaws and hyobranchial skeleton, ossifications, cranial and anterior spinal nerves, musculature, blood system and other associated anatomical features. The structure of the skeletogenous elements in general agreed with earlier descriptions. However, a rudimentary fenestra lateralis nasi is found in the nasal capsule of H. nebulosus , hitherto not reported, and a complete cartilaginous processus pterygoideus, confluent with the trabecula and inner margin of the lamina orbito-nasalis described by Edgeworth (1923 a ), was not extant in any Hynobius specimen. H. retardatus has a hypoglossal foramen (and nerve) and joins H. nebulosus (Fox 1957), Cryptobranchus japonicus and alleghaniensis as the only living Amphibia to possess this structure. The neural arch homology of the occipital crest is reaffirmed. The columella stilus of the 32 mm H. nebulosus is confluent with the pterygo-quadrate cartilage and because the hyoid and columella have a common blastematous origin in Hypogeophis (Marcus 1910), it is suggested that there was an ancestral cartilaginous continuity between the hyoid and pterygo-quadrate cartilage, similar to the commissura terminales of the branchiale. This feature would further emphasize the branchial segmental homologies of the mandibular cartilage, hyoid and branchiale. The pattern of the cranial nerves is similar to that of other urodele larvae and the arrangement of the profundus and maxillaris nerves supports the view of the descent of urodeles from porolepiforme crossopterygians (Jarvik 1942). There is a segmental series of eleven head-pharynx segments, a complete branchial segment including a levator muscle, nerve, cartilage bar and gill cleft. Each post-hyoid segment is complete except for the absence of branchiale V and VI, and behind the fourth functional gill cleft there are three vestigial blind ones and then the larynx and trachea leading to the lungs. The masseter (2nd segment), digastricus (3rd segment), dilator laryngeus (10th segment) and trapezius (11th segment) are considered to be the homologues of the other six intervening levator gill arch muscles. The arytenoid and tracheal cartilages are considered to be branchial bars of the 10th and 11th segments respectively, and the lungs to have developed from gill pouches of the 11th segment which failed to reach the exterior early in vertebrate evolution. The classical view of the homology of the laryngo-tracheal skeleton with a branchial bar enunciated by Gegenbaur and Wilder independently in 1892 is therefore upheld; disagreement is merely a numerical one. The basic segmental components of the amphibian head and pharynx are modified in ontogeny by omission, distortion or addition, in order to fit the animal for a terrestrial existence.


PLoS ONE ◽  
2012 ◽  
Vol 7 (6) ◽  
pp. e39140 ◽  
Author(s):  
Katherine A. Wilkinson ◽  
Heidi E. Kloefkorn ◽  
Shawn Hochman

1978 ◽  
Vol 1 (1) ◽  
pp. 1-2 ◽  
Author(s):  
Waltr G. Bradley
Keyword(s):  

1982 ◽  
Vol 60 (6) ◽  
pp. 850-855 ◽  
Author(s):  
Radan Čapek ◽  
Barbara Esplin

Effects of taurine and homotaurine (3-aminopropancsuIfonic acid), on excitability of primary afferents were compared with effects of γ-aminobutyric acid (GABA) in spinal unanaesthesized cats. Homotaurine and GABA, administered intravenously or topically, produced a marked increase in afferent excitability. Homotaurine was about 10 times more potent than GABA. Taurine (up to 2 mmol/kg i.v., or 10 mM topically) did not produce a consistent change in afferent excitability. The effect of homotaurine was antagonized by bicuculline or picrotoxin in doses which suppressed the primary afferent depolarization, as indicated by an increase of afferent excitability, evoked by conditioning stimulation of an antagonistic muscle nerve. Semicarbazidc, an inhibitor of GABA synthesis, did not attenuate the homotaurine-induced excitability changes of afferents while suppressing entirely the primary afferent depolarization. These findings suggest that homotaurine exerts a direct GABA-like action on feline primary afferents.


1991 ◽  
Vol 115 (3) ◽  
pp. 755-764 ◽  
Author(s):  
L Anglister

Acetylcholinesterase (AChE) in skeletal muscle is concentrated at neuromuscular junctions, where it is found in the synaptic cleft between muscle and nerve, associated with the synaptic portion of the myofiber basal lamina. This raises the question of whether the synaptic enzyme is produced by muscle, nerve, or both. Studies on denervated and regenerating muscles have shown that myofibers can produce synaptic AChE, and that the motor nerve may play an indirect role, inducing myofibers to produce synaptic AChE. The aim of this study was to determine whether some of the AChE which is known to be made and transported by the motor nerve contributes directly to AChE in the synaptic cleft. Frog muscles were surgically damaged in a way that caused degeneration and permanent removal of all myofibers from their basal lamina sheaths. Concomitantly, AChE activity was irreversibly blocked. Motor axons remained intact, and their terminals persisted at almost all the synaptic sites on the basal lamina in the absence of myofibers. 1 mo after the operation, the innervated sheaths were stained for AChE activity. Despite the absence of myofibers, new AChE appeared in an arborized pattern, characteristic of neuromuscular junctions, and its reaction product was concentrated adjacent to the nerve terminals, obscuring synaptic basal lamina. AChE activity did not appear in the absence of nerve terminals. We concluded therefore, that the newly formed AChE at the synaptic sites had been produced by the persisting axon terminals, indicating that the motor nerve is capable of producing some of the synaptic AChE at neuromuscular junctions. The newly formed AChE remained adherent to basal lamina sheaths after degeneration of the terminals, and was solubilized by collagenase, indicating that the AChE provided by nerve had become incorporated into the basal lamina as at normal neuromuscular junctions.


2001 ◽  
Vol 110 (9) ◽  
pp. 801-810 ◽  
Author(s):  
Norman D. Hogikyan ◽  
Melanie Urbanchek ◽  
Michael M. Johns ◽  
William R. Carroll ◽  
Paul R. Kileny ◽  
...  

There is no current treatment method that can reliably restore physiologic movement to a paralyzed vocal fold. The purposes of this study were to test the hypotheses that 1) muscle-nerve-muscle (M-N-M) neurotization can be induced in feline laryngeal muscles and 2) M-N-M neurotization can restore movement to a paralyzed vocal fold. Muscle-nerve-muscle neurotization can be defined as the reinnervation of a denervated muscle via axons that are induced to sprout from nerves within an innervated muscle and that then traverse a nerve graft interposed between it and the target denervated muscle. a paralyzed laryngeal muscle could be reinnervated by axons from its contralateral paired muscle, thus achieving motion-specific reinnervation. Eighteen adult cats were divided into sham, hemilaryngeal-denervated, and M-N-M—reinnervated thyroarytenoid muscle groups. Five of the 6 reinnervated animals had histologic evidence of axons in the nerve graft, 4 of the 6 had evoked electromyographic evidence of crossed reinnervation, and 1 of the 6 had a return of appropriately phased adduction. This technique has great potential and should be further investigated.


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