Sensory innervation of the Achilles tendon by group III and IV afferent fibers

1985 ◽  
Vol 172 (2) ◽  
pp. 145-156 ◽  
Author(s):  
K. H. Andres ◽  
M. D�ring ◽  
R. F. Schmidt
Keyword(s):  
Achilles Tendon ◽  
Sensory Innervation ◽  
Group Iii ◽  
Afferent Fibers

Inhibition of cardiac vagal component of baroreflex by group III and IV afferents

1991 ◽  
Vol 260 (3) ◽  
pp. H730-H734 ◽  
Author(s):  
P. N. McWilliam ◽  
T. Yang
Keyword(s):  
Peroneal Nerve ◽  
Baroreceptor Reflex ◽  
Interval Prolongation ◽  
Group Iii ◽  
Control Value ◽  
Pressure Elevation ◽  
Group I ◽  
Afferent Fibers ◽  
The Difference ◽  
The Right

The action of electrically evoked activity in somatic afferent fibers on the sensitivity of the baroreceptor reflex was examined in decerebrate cats. The sensitivity of the reflex was expressed as the difference between the maximum prolongation of R-R interval in response to carotid sinus pressure elevation and the mean of 10 R-R intervals immediately before pressure elevation. The control value of R-R interval prolongation was 192 +/- 50 ms. Stimulation (10 Hz) of group I and II fibers of the right peroneal nerve (evoked volleys recorded from the sciatic nerve) had no effect on R-R interval prolongation (171 +/- 45 ms). Recruitment of group III fibers (10 Hz) conducting at 23.6 +/- 0.65 m/s reduced the prolongation of R-R interval to 52 +/- 14 ms. Recruitment of group IV fibers (10 Hz) conducting less than 2.5 m/s further reduced the prolongation of R-R interval to 1.0 +/- 8.0 ms. It is concluded that the inhibition of the cardiac vagal component of the baroreceptor reflex produced by electrical stimulation of the peroneal nerve is mediated by afferent fibers of groups III and IV.

The Potential Role of Human Derived Amniotic Membrane Graft in The Repair of Induced Tendon Tear in Adult Male Albino Rat: Histological Study

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Dalia Ahmed Yousef Yehia ◽  
Somaya Abd Al Aleem Mohammed ◽  
Gehan Khalaf Megahed ◽  
Nevine Bahaa El din Mohamed Soliman
Keyword(s):  
Achilles Tendon ◽  
Adult Male ◽  
Amniotic Membrane ◽  
Treated Group ◽  
Human Amniotic Membrane ◽  
Tendon Tear ◽  
Group Iii ◽  
Tendon Tears ◽  
Group Ii

Abstract Introduction Achilles tendon tears cause severe impairment in patient mobility and productivity, causing significant reduction in the quality of life. Many complications are associated with the tendon healing process such as peritendinous adhesions and excessive fibrotic scars. Unsatisfactory results appeared with the existing medical and surgical treatments to regain full tendon structure and function. Amniotic membrane is avascular, and characterized by low immunogenicity, anti-inflammatory, antiscarring properties. These criteria render it as a natural biological substitute and a novel therapeutic alternative for tendon tears. Aim: The aim of the work was to study the effect of human amniotic membrane graft application on the repair of induced Achilles tendon tear. Material and methods Fresh human amniotic membrane (AM) grafts were prepared from harvested human full-term caesarian sections-delivered placentas. Thirty adult male albino rats were divided into 3 equal groups (n = 10); group I (control group), group II (tendon tear group) and group III (AM treated group). After anesthesia, a full thickness transverse incision was induced in the rat right Achilles tendons of group II and III. Human derived amniotic membrane graft measuring 1 cm2 was applied circumferentially on the tendon tear in group III. Rats were sacrificed after 28 days. Results After the tendon tear, the untreated group (II) showed gradual accumulation of fat cells replacing the collagen bundles in focal areas. Areas of mononuclear cellular infiltration were demonstrated. The AM-treated group showed many thick parallel regularly arranged collagen fibers with a significant increase in the collagen fibers area percentage. It also showed apparent increase in tenoblasts with regular organization and apparent decrease of mononuclear inflammatory cells. Conclusion This study demonstrated the potential therapeutic role of the application of human amniotic membrane grafts in the repair of Achilles tendon tears, suggesting a future alternative therapy for patients suffering from Achilles tendon tears.

Sensing vascular distension in skeletal muscle by slow conducting afferent fibers: neurophysiological basis and implication for respiratory control

2004 ◽  
Vol 96 (2) ◽  
pp. 407-418 ◽  
Author(s):  
Philippe Haouzi ◽  
Bruno Chenuel ◽  
Andrew Huszczuk
Keyword(s):  
Arterial Occlusion ◽  
Respiratory Control ◽  
Vascular Network ◽  
Mechanical Stimuli ◽  
Peripheral Vascular ◽  
Group Iii ◽  
Arterial Blood ◽  
Afferent Fibers ◽  
Muscle Afferent ◽  
Neurophysiological Basis

This review examines the evidence that skeletal muscles can sense the status of the peripheral vascular network through group III and IV muscle afferent fibers. The anatomic and neurophysiological basis for such a mechanism is the following: 1) a significant portion of group III and IV afferent fibers have been found in the vicinity and the adventitia of the arterioles and the venules; 2) both of these groups of afferent fibers can respond to mechanical stimuli; 3) a population of group III and IV fibers stimulated during muscle contraction has been found to be inhibited to various degrees by arterial occlusion; and 4) more recently, direct evidence has been obtained showing that a part of the group IV muscle afferent fibers is stimulated by venous occlusion and by injection of vasodilatory agents. The physiological relevance of sensing local distension of the vascular network at venular level in the muscles is clearly different from that of the large veins, since the former can directly monitor the degree of tissue perfusion. The possible involvement of this sensing mechanism in respiratory control is discussed mainly in the light of the ventilatory effects of peripheral vascular occlusions during and after muscular exercise. It is proposed that this regulatory system anticipates the chemical changes that would occur in the arterial blood during increased metabolic load and attempts to minimize them by adjusting the level of ventilation to the level of muscle perfusion, thus matching the magnitudes of the peripheral and pulmonary gas exchange.

KV7 Channels are Potential Regulators of the Exercise Pressor Reflex

2021 ◽  
Author(s):  
Andrew B Wright ◽  
Khrystyna Yu Sukhanova ◽  
Keith S Elmslie
Keyword(s):  
Neuronal Excitability ◽  
Specific Inhibitor ◽  
Group Iii ◽  
Kv7 Channels ◽  
Exercise Pressor Reflex ◽  
Arterial Blood ◽  
Afferent Fibers ◽  
Muscle Afferent ◽  
Pressor Reflex ◽  
Exercise Induced

The exercise pressor reflex (EPR) originates in skeletal muscle and is activated by exercise-induced signals to increase arterial blood pressure and cardiac output. Muscle ischemia can elicit the EPR, which can be inappropriately activated in patients with peripheral vascular disease or heart failure to increase the incidence of myocardial infarction. We seek to better understand the receptor/channels that control excitability of group III and group IV muscle afferent fibers that give rise to the EPR. Bradykinin (BK) is released within contracting muscle and can evoke the EPR. However, the mechanism is incompletely understood. KV7 channels strongly regulate neuronal excitability and are inhibited by BK. We have identified KV7 currents in muscle afferent neurons by their characteristic activation/deactivation kinetics, enhancement by the KV7 activator retigabine, and block by KV7 specific inhibitor XE991. The block of KV7 current by different XE991 concentrations suggests that the KV7 current is comprised of both KV7.2/7.3 (high affinity) and KV7.5 (low affinity) channels. The KV7 current was inhibited by 300 nM BK in neurons with diameters consistent with both group III and IV afferents. The inhibition of KV7 by BK could be a mechanism by which this metabolic mediator generates the EPR. Furthermore, our results suggest that KV7 channel activators such as retigabine, could be used to reduce cardiac stress resulting from the exacerbated EPR in patients with cardiovascular disease.

Dynamic exercise stimulates group III muscle afferents

1994 ◽  
Vol 71 (2) ◽  
pp. 753-760 ◽  
Author(s):  
J. G. Pickar ◽  
J. M. Hill ◽  
M. P. Kaufman
Keyword(s):  
Receptive Field ◽  
Receptive Fields ◽  
Muscle Afferents ◽  
Dynamic Exercise ◽  
Triceps Surae ◽  
Step Cycle ◽  
Group Iii ◽  
Afferent Fibers ◽  
Triceps Surae Muscles ◽  
Flexor Digitorum

1. In decerebrate cats, we investigated the responses of group III muscle afferents to dynamic exercise. The cats performed low intensity dynamic exercise on a treadmill. Group III afferent activity from the dynamically exercising triceps surae muscles was recorded from L7-S1 dorsal root filaments. 2. Single-unit recordings were obtained from 15 group III afferent fibers whose receptive fields were in the triceps surae muscles and from one group III afferent whose receptive field was in the flexor digitorum longus muscle. Conduction velocities for the 16 group III afferents ranged from 3.0 to 27.9 m/s (15.6 +/- 1.9 m/s, mean +/- SE). 3. Ten of 16 group III muscle afferents were stimulated by dynamic exercise. Of the 10, 7 were strongly responsive and 3 were mildly responsive to dynamic exercise. Each of the 10 afferents displayed at least some activity that was synchronized to the contraction phase of the step cycle. The mean developed tensions for strongly responsive afferents, mildly responsive afferents, and afferents that did not respond were 0.8 +/- 0.3, 1.3 +/- 0.5, and 0.7 +/- 0.3 Kg, respectively (P > 0.05). Thus differences in the responsiveness of the afferents to exercise were not attributable to differences in developed tensions. 4. The group III afferents that were strongly responsive to dynamic exercise were also mechanically sensitive. Each strongly responsive afferent (n = 7) was stimulated by nonnoxious pressure applied to its receptive field. Most strongly responsive afferents (n = 5) were stimulated by stretch of the triceps surae muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

Sensory Fibers of the Pelvic Nerve Innervating the Rat's Urinary Bladder

2000 ◽  
Vol 84 (4) ◽  
pp. 1924-1933 ◽  
Author(s):  
V. K. Shea ◽  
R. Cai ◽  
B. Crepps ◽  
J. L. Mason ◽  
E. R. Perl
Keyword(s):  
Urinary Bladder ◽  
Conduction Velocity ◽  
Receptive Fields ◽  
The Body ◽  
Sensory Innervation ◽  
Pelvic Nerve ◽  
Ureterovesical Junction ◽  
Bladder Filling ◽  
Afferent Fibers ◽  
Conduction Velocities

Much attention has been given to the pelvic nerve afferent innervation of the urinary bladder; however, reports differ considerably in descriptions of afferent receptor types, their conduction velocities, and their potential roles in bladder reflexes and sensation. The present study was undertaken to do a relatively unbiased sampling of bladder afferent fibers of the pelvic nerve in adult female rats. The search stimulus for units to be studied was electrical stimulation of both the bladder nerves and the pelvic nerve. Single-unit activity of 100 L6 dorsal root fibers, activated by both pelvic and bladder nerve stimulation, was analyzed. Sixty-five units had C-fiber and 35 units had Aδ-fiber conduction velocities. Receptive characteristics were established by direct mechanical stimulation, filling of the bladder with 0.9% NaCl at a physiological speed and by filling the bladder with solutions containing capsaicin, potassium, or turpentine oil. The majority (61) of these fibers were unambiguously excited by bladder filling with 0.9% NaCl and were classified as mechanoreceptors. All mechanoreceptors with receptive fields on the body of the bladder had low pressure thresholds (≤10 mmHg). Receptive fields of units with higher thresholds were near the ureterovesical junction, on the base of the bladder or could not be found. Neither thresholds nor suprathreshold responses could be related to conduction velocity. Bladder compliance and mechanoreceptor thresholds were influenced by the stage of the estrous cycle: both were lowest in proestrous rats and highest in metaestrous rats. Mechanoreceptors innervating the body of the bladder and the region near the ureterovesical junction showed two patterns of responsiveness to slow bladder filling. One group of units exhibited increasing activity with increasing pressure up to 40 mmHg, while the other group showed a peak in activity at pressures below 40 mmHg followed by a plateau or decrease in activity with increasing pressure. It is proposed that differences in stimulus transduction relate to the different response patterns. Thirty-nine units failed to respond to bladder filling. Eight of these were excited by intravesical potassium or capsaicin and were classified as chemoreceptors. The remaining 31 units were not excited by any stimulus tested. Chemoreceptors and unexcited units had both Aδ and C afferent fibers. We conclude that the pelvic nerve sensory innervation of the rat bladder is complex, may be sensitive to hormonal status, and that the properties of individual sensory receptors are not related in an obvious manner to the conduction velocity of their fibers.

Fine sensory innervation of the knee joint capsule by group III and group IV nerve fibers in the cat

1995 ◽  
Vol 351 (3) ◽  
pp. 415-428 ◽  
Author(s):  
B. Heppelmann ◽  
K. Messlinger ◽  
W. F. Neiss ◽  
R. F. Schmidt
Keyword(s):  
Knee Joint ◽  
Nerve Fibers ◽  
Group Iv ◽  
Joint Capsule ◽  
Sensory Innervation ◽  
Group Iii
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