Target finding of pain nerve fibers: Neural growth mechanisms in the tooth pulp

2007 ◽  
Vol 92 (1-2) ◽  
pp. 40-45 ◽  
Author(s):  
Kaj Fried ◽  
Christina Lillesaar ◽  
Wondossen Sime ◽  
Nina Kaukua ◽  
Manuel Patarroyo
Keyword(s):  
Nerve Fibers ◽  
Tooth Pulp ◽  
Growth Mechanisms ◽  
Neural Growth

scholarly journals QUANTITATIVE ULTRASTRUCTURAL ANALYSIS OF NEUROTUBULAR APPARATUS OF THE MYELIN FIBERS OF DENTAL PULP IN CHILDREN BORN AND LIVING IN PLACES WITH HIGH ECOLOGICAL AND TECHNOGENIC LOAD

2019 ◽  
Vol 29 (2) ◽  
pp. 206-212
Author(s):  
O.L. Polyakova ◽  
N.N. Chuchkova ◽  
V.M. Chuchkov ◽  
V.N. Nikolenko
Keyword(s):  
Nerve Fibers ◽  
Machine Building ◽  
Living Conditions ◽  
Neurovascular Bundle ◽  
Permanent Teeth ◽  
Tooth Pulp ◽  
Chemical Plants ◽  
The Republic ◽  
Large Motor ◽  
Definition Of

The purpose of the study is a quantitative analysis of myelin nanotubular apparatus of the conductors included in the neurovascular bundle of the tooth pulp in children born and living in places with high ecological and technogenic load. The object of the study was the neurovascular bundle of the tooth (№ 540), removed for medical reasons, in children aged 5 to 14 years (the period of eruption of permanent teeth), living in conditionally favorable areas of Udmurtia and in places with high ecological and technogenic load. Areas with high ecological and technogenic load were considered to be places near the machine-building plant, poultry farms, large motor transport enterprises and highways, etc. (Izhevsk); location of the largest oil depot in the Republic, asphalt and chemical plants of the Kama region of the Republic (Kambarka); the territory of woodworking, furniture factories, woodworking factory “Red Star” (Mozhga); forestry industry (Uva). The influence of living conditions on the composition and ultrastructural provision of the myelin nerve fibers of the tooth pulp is shown: the number of microtubules (regardless of the fiber diameter) and neurophilaments (for conductors of large and small diameters) in the conditions of ecological and technogenic load is reduced. It is noted that differences in living conditions (places with ecological and technogenic load) do not affect the ultrastructural provision of myelin conductors at the time of eruption of permanent teeth (5 years), but quantitative changes progress over time, starting from the period of second childhood (8-12 years) reaching maximum values by the age of 14. The age of 11 years is a critical period with regard to the definition of the neurotubular apparatus of myelin nerves in children living in places with unfavorable ecological and technogenic load.

Axon Reflex Vasodilatation in Cat Dental Pulp Elicited by Noxious Stimulation of the Gingiva

1994 ◽  
Vol 73 (12) ◽  
pp. 1797-1802 ◽  
Author(s):  
T. Sasano ◽  
S. Kuriwada ◽  
N. Shoji ◽  
D. Sanjo ◽  
H. Izumi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Dental Pulp ◽  
Inferior Alveolar Nerve ◽  
Nerve Fibers ◽  
Sensory Nerves ◽  
Tooth Pulp ◽  
Noxious Stimulation ◽  
Antidromic Activation ◽  
Axon Reflex ◽  
Stimulation Of

Antidromic stimulation of sensory nerves has been shown to increase blood flow in the tissue they innervate. This study was designed to determine if antidromic vasomotor responses occur in feline dental pulp and if they are mediated by branched axons supplying both tooth pulp and gingiva. Dynamic changes in pulpal blood flow (PBF) elicited by electrical stimulation, pinching, heating, and capsaicin application to the gingivae were investigated in cat mandibular canine teeth by means of Laser Doppler Velocimetry. All inferior alveolar nerve bundles and the cervical sympathetic trunk had been previously sectioned to avoid the occurrence of brainstem reflexes, e.g., somato-autonomic vasomotor reflexes. Increases in PBF were observed in seven out of 12 cats when a restricted gingival area adjacent to the canine teeth was stimulated as described, but the increases were abolished after the sensitive gingival area was painted with lidocaine jelly, a surface anesthetic. These vasodilator responses, remarkably reduced following repeated application of 30 mM of capsaicin, are considered to be induced via antidromic activation of capsaicin-sensitive nociceptive nerve fibers, presumably by axon reflex mechanisms, suggesting that nerve terminals supplying the gingiva originate from parent axons which have collaterals that innervate the canine tooth pulp.

Capsaicin-sensitive Aδ Fibers in Cat Tooth Pulp

1997 ◽  
Vol 76 (7) ◽  
pp. 1341-1349 ◽  
Author(s):  
H. Ikeda ◽  
Y. Tokita ◽  
H. Suda
Keyword(s):  
Nerve Fibers ◽  
The Other ◽  
Tooth Pulp ◽  
High Concentration ◽  
Excitatory Effect ◽  
Low Concentration ◽  
C Fibers ◽  
Capsaicin Application ◽  
Conduction Velocities ◽  
Neural Discharge

How close a correlation there is between the conduction velocity and receptive properties of pulpal nerve fibers is still unclear. Our specific aims were to confirm whether: (1) capsaicin affects not only polymodal C fibers but A8 fibers as well, and (2) Aδ polymodal nociceptors exist in the tooth pulp. A total of 139 functional single cat tooth pulp nerve fibers was isolated for analysis, of which 21 were Ap, 37 C, and 81 AS fibers. The A8 fibers were divided into two groups: One (n = 38) consisted of those fibers whose conduction velocities were more than 2.0 m/s both inside and outside the tooth pulp, and the other (n = 43) consisted of those fibers whose intrapulpal conduction velocities were less than 2.0 m/s, with extrapulpal conduction velocities greater than 2.0 m/s. We used 82 fibers to record the neural response following the topical application of capsaicin for 60 min at increasing concentrations (1 nM, 100 nM, 10 μM) through thin dentin. Six of 25 slow Aδ, 10/20 C, and no Ap (0/11) or fast AS (0/26) fibers responded to 1 nM or 100 nM of capsaicin. When the three concentrations of capsaicin solution were applied in turn, the electrical threshold and latency of Aβ and fast AS fibers did not change, whereas those of slow AS and C fibers gradually increased. In 0/11 Ap, 0/26 fast AS, 13/25 slow AS, and 18/20 C fibers, the conduction was blocked reversibly or irreversibly following the application of 10 uM of capsaicin. The amplitude of the late component of antidromic action potential of fast AS fibers decreased after the capsaicin application. No neural discharge could be recorded from 19 (3 Aβ, 5 fast AS, 6 slow AS, and 5C) fibers following the application of a single high concentration of capsaicin (10 μM). A single low concentration of capsaicin (100 nM) activated only some slow-conducting fibers (0/4 Ap, 0/4 FAS, 3/6 SAS, and 4/6 C). Response properties recorded from the remaining 18 fibers (3 Ap, 3 fast AS, 6 slow Aδ, and 6 C) were not changed following the application of the control vehicle. These results confirm that a low concentration of capsaicin has an excitatory effect on the response of slow pulpal AS as well as C fibers, and that a high concentration of capsaicin blocks the conduction of slow Aδ and C fibers as well as the terminals of fast AS fibers in the pulp.

The growth of mica polytypes as studied by conventional and high-resolution TEM

1983 ◽  
Vol 41 ◽  
pp. 174-177
Author(s):  
A. Baronnet ◽  
M. Amouric
Keyword(s):  
Water Pressure ◽  
Point Of View ◽  
Temperature Fields ◽  
Natural Occurrence ◽  
Growth Mechanisms ◽  
Long Period ◽  
High Resolution Tem ◽  
Layer Stacking ◽  
Experimental Works ◽  
Potential Use

The origin of mica polytypes has long been a challenging problem for crystal- lographers, mineralogists and petrologists. From the petrological point of view, interest in this field arose from the potential use of layer stacking data to furnish further informations about equilibrium and/or kinetic conditions prevailing during the crystallization of the widespread mica-bearing rocks. From the compilation of previous experimental works dealing with the occurrence domains of the various mica "polymorphs" (1Mr, 1M, 2M1, 2M2 and 3T) within water-pressure vs temperature fields, it became clear that most of these modifications should be considered as metastable for a fixed mica species. Furthermore, the natural occurrence of long-period (or complex) polytypes could not be accounted for by phase considerations. This highlighted the need of a more detailed kinetic approach of the problem and, in particular, of the role growth mechanisms of basal faces could play in this crystallographic phenomenon.

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