Effects of aging on numbers, sizes and conduction velocities of myelinated and unmyelinated fibers of the pelvic nerve in rats

Nakayama, Hitomi; Noda, Kôichi; Hotta, Harumi; Ohsawa, Hideo; Hosoya, Yoshinori

doi:10.1016/s0165-1838(98)00013-7

Cited by 38 publications

(28 citation statements)

References 30 publications

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“…Facilitated mechanical response was also observed in mechanoresponsive muscular C-fibers. This pattern of altered mechanical sensitivity combined with a reduced number of mechanoresponsive unmyelinated C-fibers is also observed in aging 28,29,51,53 and diabetic neuropathy, 18,36 and may also correspond with reports of small-fiber polyneuropathy in some patients diagnosed with fibromyalgia 32 and restless legs syndrome. 38 These changes seem to be related with decreased neurotrophic factors in primary sensory neurons, 3,18 however, in a reserpine-induced pain model, no apparent histological changes were detected in the sciatic nerve bundle and DRG by light microscopy, 27 which suggests that this paradoxical change in mechanical sensitivity likely results from reserpine-mediated functional alterations in the peripheral nervous system.…”

Section: Peripheral Mechanisms Of Altered Nociceptionsupporting

confidence: 79%

Peripheral and spinal mechanisms of nociception in a rat reserpine-induced pain model

Taguchi

Katanosaka

Yasui

et al. 2015

Pain

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Chronic widespread pain is a serious medical problem, yet the mechanisms of nociception and pain are poorly understood. Using a reserpine-induced pain model originally reported as a putative animal model for fibromyalgia, this study was undertaken to examine the following: (1) expression of several ion channels responsible for pain, mechanotransduction, and generation/propagation of action potentials in the dorsal root ganglion (DRG), (2) activities of peripheral nociceptive afferents, and (3) alterations in spinal microglial cells. A significant increase in mRNA expression of the acid-sensing ion channel (ASIC)-3 was detected in the DRG, and the behavioral mechanical hyperalgesia was significantly reversed by subcutaneous injection of APETx2, a selective blocker of ASIC3. Single-fiber recordings in vitro revealed facilitated mechanical responses of mechanoresponsive C-fibers both in the skin and muscle although the proportion of mechanoresponsive C-nociceptors was paradoxically decreased. In the spinal dorsal horn, microglial cells labeled with Iba1 immunoreactivity was activated, especially in laminae I-II where the nociceptive input is mainly processed compared with the other laminae. The activated microglia and behavioral hyperalgesia were significantly tranquilized by intraperitoneal injection of minocycline. These results suggest that the increase in ASIC3 in the DRG facilitated mechanical response of the remaining C-nociceptors and that activated spinal microglia may direct to intensify pain in this model. Pain may be further amplified by reserpine-induced dysfunction of the descending pain inhibitory system and by the decrease in peripheral drive to this system resulting from a reduced proportion of mechanoresponsive C-nociceptors.

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Section: Peripheral Mechanisms Of Altered Nociceptionsupporting

confidence: 79%

Peripheral and spinal mechanisms of nociception in a rat reserpine-induced pain model

Taguchi

Katanosaka

Yasui

et al. 2015

Pain

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“…Our data were corroborated by Sakita et al (2016) who also demonstrated maintenance of the G ratios of the tibial nerve of rats between 20 weeks and 90 weeks of age. Nakayama et al (1998) reported that there was no reduction in the rate of conduction of action potentials in the MF of old rats. Despite this, Jeronimo et al (2008) found a significant reduction of the G ratio at the age of 720 days.…”

Section: Discussionmentioning

confidence: 99%

Effects of Strength Training and Anabolic Steroid in the Peripheral Nerve and Skeletal Muscle Morphology of Aged Rats

Neto

Silva

Ciena

et al. 2017

Front. Aging Neurosci.

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Thirty male 20-month-old Wistar rats were divided into groups: IC—initial control (n = 6), FC—final control (n = 6), AC—anabolic hormone control (n = 6), ST—strength trained (n = 6) and STA—strength trained with anabolic hormone (n = 6). All groups were submitted to adaptation, familiarization and maximum load carrying test (MLCT). Strength training (6–8×/session with loads of 50%–100% MLCT, 3×/week and pause of 120 s) was performed in ladder climbing (LC) for 15 weeks. The administration of testosterone propionate (TP) was performed 2×/week (10 mg/kg) in animals in the AC and STA groups. After the experimental period, animals were euthanized and the tibial nerve and plantaris muscle removed and prepared for electron transmission and histochemistry. To compare the groups we used one-way ANOVA (post hoc Bonferroni), student’s t-tests for pre vs. post (dependent and independent variables) comparisons and significance level set at p ≤ 0.05. The following significant results were found: (a) aging decreased the number of myelinated axon fibers; (b) use of isolated TP increased the diameter of myelinated fibers, along with increased thickness of myelin sheath; (c) ST increased area of myelinated and unmyelinated fibers, together with the myelin sheath. These changes made it possible to increase the area occupied by myelinated fibers keeping their quantity and also reduce the interstitial space; and (d) association of anabolic steroid and ST increased the area of unmyelinated axons and thickness of the myelin sheath. Compared to ST, both strategies have similar results. However, Schwann cells increased significantly only in this strategy.

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“…Age‐related changes in the intramural plexus of the urinary bladder have been previously studied. In aged rats, the unmyelinated fibers have been shown to decrease significantly in the number of fibers smaller than 0.7 μm in diameter, while they have not been shown to change significantly in maximum conduction velocity (Italiano et al, 1995; Nakayama et al, 1998). Aging is associated with a large increase in bladder volume (Lepor et al, 1992; Hotta et al, 1995) as well as a reduced sensitivity of pelvic nerve afferents to volume, and a reduced ability to raise bladder pressure during contraction of bladder smooth muscle (Hotta et al, 1995).…”

Section: Methodsmentioning

confidence: 99%

Age‐related changes in urinary bladder intramural neurons

Mizuno

Pompeu

Castelucci

et al. 2007

Intl J of Devlp Neuroscience

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A quantitative morphometric evaluation of the intramural plexus of the urinary bladder of adult and aged guinea-pigs was performed by histological analysis, scanning electron microscopy, and hystochemical methods, such as NADH-diaphorase and acetylcholinesterase (AChE). The round or oval shaped intramural neurons were revealed among the bundles of the smooth detrusor muscle in clusters containing a variable number of cells in the groups. In both adult control and aged animals, the ganglia were enveloped by a ganglionar capsule of connective tissue mainly composed of type I collagen fibers. The number of neurons NADH-diaphorase positives estimated in the intramural plexus was 1433+/-187.71 and 1107+/-120.67 in the adult control and aged groups, respectively. The perikaryon areas of the NADH-diaphorase neurons reactives ranged from 216.40 to 1809.30 microm(2) in adult control group and from 198.20 to 2096.25 microm(2) in aged group. The nuclear area showed an increase in aged animals. The number of AChE-positive neurons estimated in the intramural plexus was 3294.67+/-415 microm(2) in the adult control group and 1960.33+/-526 microm(2) in the aged group, showing a significant decrease in the latter group. This age-related morphological change in intramural neurons may contribute to changes in urinary bladder activities in the elderly.

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Effects of aging on numbers, sizes and conduction velocities of myelinated and unmyelinated fibers of the pelvic nerve in rats

Cited by 38 publications

References 30 publications

Peripheral and spinal mechanisms of nociception in a rat reserpine-induced pain model

Peripheral and spinal mechanisms of nociception in a rat reserpine-induced pain model

Effects of Strength Training and Anabolic Steroid in the Peripheral Nerve and Skeletal Muscle Morphology of Aged Rats

Age‐related changes in urinary bladder intramural neurons

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