A C-fiber reflex modulated by heterotopic noxious somatic stimuli in the rat

1994 ◽  
Vol 72 (1) ◽  
pp. 194-213 ◽  
Author(s):  
S. Falinower ◽  
J. C. Willer ◽  
J. L. Junien ◽  
D. Le Bars

1. Electromyographic recordings were made from the biceps femoris muscle through a pair of noninsulated platinum/iridium needle electrodes in male Sprague-Dawley rats artificially ventilated and anesthetized with 0.8% halothane in a N2O-O2 mixture (2/3:1/3). The animals' ventilation, heart rates, and body temperatures were continuously monitored. Electrical stimuli (2-ms duration, 0.16 Hz) were delivered to the sural nerve territory through a pair of noninsulated platinum/iridium needle electrode inserted subcutaneously in the medial aspect of the 4th and the lateral part of the 5th toe. Such stimulation elicited a two-component reflex response in the ipsilateral biceps femoris muscle: The first had a short latency (17.5 +/- 2.3 ms), short duration (20.7 +/- 2.6 ms), and low threshold (1.5 +/- 0.6 mA), whereas the second had a longer latency (162.4 +/- 5.1 ms), longer duration (202.3 +/- 6.2 ms), and higher threshold (5.7 +/- 0.5 mA). 2. Lidocaine (0.02–0.1%; 0.1 ml), but not saline, injected subcutaneously over the proximal part of the sural nerve, produced a selective depression of the late component of the reflex response, whereas the first component remained unchanged. The conduction velocity of the afferent fibers was estimated from the stimulation needles in the sural nerve territory to the nerve's projection in the lumbar spinal cord: it was concluded that the second, late component of the reflex response was due to afferent signals transmitted via unmyelinated C-fibers, whereas the first component was related to activation of fine myelinated fibers (A delta group). 3. Electrical stimulation of the sural nerve was still able to elicit the two-component reflex responses in the ipsilateral biceps femoris muscle of chronic spinal rats, indicating that these responses were genuine reflex responses, transmitted completely through a spinal circuit. 4. The C-fiber reflex was recorded when the duration and frequency of the stimuli applied to the sural nerve varied within the 0.5- to 4-ms and 0.02- to 1-Hz ranges, respectively. It was concluded that a single 2-ms duration shock at an intensity of 1.2 times the C-fiber reflex threshold, delivered every 6 s (0.16 Hz), constituted an acceptable and optimal protocol for experiments in which the C-fiber reflex was studied as a function of time. These parameters were used throughout the subsequent experiments.(ABSTRACT TRUNCATED AT 400 WORDS)

1998 ◽  
Vol 79 (5) ◽  
pp. 2557-2567 ◽  
Author(s):  
Léon Plaghki ◽  
Dominique Bragard ◽  
Daniel Le Bars ◽  
Jean-Claude Willer ◽  
Jean-Marie Godfraind

Plaghki, Léon, Dominique Bragard, Daniel Le Bars, Jean-Claude Willer, and Jean-Marie Godfraind. Facilitation of a nociceptive flexion reflex in man by nonnoxious radiant heat produced by a laser. J. Neurophysiol. 79: 2557–2567, 1998. Electromyographic recordings were made in healthy volunteers from the knee-flexor biceps femoris muscle of the nociceptive RIII reflex elicited by electrical stimulation of the cutaneous sural nerve. The stimulus intensity was adjusted to produce a moderate pricking-pain sensation. The test responses were conditioned by a nonnoxious thermal (≤40°C) stimulus applied to the receptive field of the sural nerve. This stimulus was delivered by a CO2 laser stimulator and consisted of a 100-ms pulse of heat with a beam diameter of 20 mm. Its power was 22.7 ± 4.2 W (7.2 mJ/mm2), and it produced a sensation of warmth. The maximum surface temperature reached at the end of the period of stimulation was calculated to be 7°C above the actual reference temperature of the skin (32°C). The interval between the laser (conditioning) and electrical (test) stimuli was varied from 50 to 3,000 ms in steps of 50 ms. It was found that the nociceptive flexion reflex was facilitated by the thermal stimulus; this modulation occurred with particular conditioning-test intervals, which peaked at 500 and 1,100 ms with an additional late, long-lasting phase between 1,600 and 2,300 ms. It was calculated that the conduction velocities of the cutaneous afferent fibers responsible for facilitating the RIII reflex, fell into three ranges: one corresponding to Aδ fibers (3.2 m/s) and two in the C fiber range (1.3 and 0.7 m/s). It is concluded that information emanating from warm receptors and nociceptors converges. In this respect, the present data show, for the first time, that in man, conditioning nonnociceptive warm thermoreceptive Aδ and C fibers results in an interaction at the spinal level with a nociceptive reflex. This interaction may constitute a useful means whereby signals add together to trigger flexion reflexes in defensive reactions and other basic motor behaviors. It also may contribute to hyperalgesia in inflammatory processes. The methodology used in this study appears to be a useful noninvasive tool for exploring the thermoalgesic mechanisms in both experimental and clinical situations.


Cephalalgia ◽  
1988 ◽  
Vol 8 (3) ◽  
pp. 193-201 ◽  
Author(s):  
Giuseppe Micieli ◽  
Marco Magri ◽  
Giorgio Sandrini ◽  
Cristina Tassorelli ◽  
Giuseppe Nappi

In this study the variations in pupil diameter induced by different stimuli (dark-light adaptation, light reflex, electric stimulation of the sural nerve) were investigated in episodic (in the active or remission phases) and in chronic cluster headache (CH) patients. Pupil size monitoring was performed with a monocular, infrared TV pupillometer, and sural nerve stimuli were applied after the pain threshold had been measured as the flexion reflex threshold of the biceps femoris muscle (RIII reflex). The results were compared with those obtained in patients with “peripheral” (third neuron) Horner's syndrome and in healthy sex- and age-matched controls. On the symptomatic side we found an impairment of pupil response to light flashes and nociceptive stimuli; similar findings were sometimes evident on the pain-free side, too. These results substantiate previous observations that in cluster headache a dysfunction of the integrative central nervous system pathways also exists intercritically and mostly bilaterally, involving both autonomic regulation and pain perception mechanisms.


Author(s):  
Miloslav Fabok ◽  
Bojan Leontijević ◽  
Lazar Tomić ◽  
Milivoj Dopsaj

The main aim of this study was to define the quantitative neuromuscular characteristics of Biceps Femoris muscle (BF) as the knee joint flexor, i.e. the major synergist of caudal body in all specific movement tasks of a football player, measured by tensiomyography (TMG) method . The secondary aim of the study was to compare all TMG-BF characteristics in relation to bilateral dimorphism, as well as to compare dominant and non-dominant legs. The research was conducted on a sample which included 54 professional players of age 23.0 ± 4.4 years; body height: 182.6 ± 15.1 cm; body mass: 81.2 ± 15.1 kg; BMI: 23.3 ± 1.2 kg/cm2. TMG variables were measured on the muscles during a transition training phase (mid-season and end of the season). The results have shown that the average Tc - 32.19 ± 7.64 and 33.21 ± 8.88 ms, Td - 25.56 ± 3.58 and 25.44 ± 3.20 ms, and Dm - 7.39 ± 1.87 and 7.52 ± 2.50 mm, for dominant and non-dominant leg, respectively. The results have indicated that there was no statistically significant difference between the examined TMG variables of dominant and non-dominant leg (Wilks' lambda Value = 0.979, F=0.300, p=0.952, Part. Ƞ2 = 0.021). It may be stated that there are no differences in the manifestation of neuromuscular characteristics in healthy elite football players regardless of their dominant leg. A high level of preparedness in football in addition to a completely healthy status of the body and locomotor system result in a complete neuromuscular contractile symmetry BF of both legs.


2004 ◽  
Vol 47 (4) ◽  
pp. 367-375 ◽  
Author(s):  
T. Kisiel ◽  
J. M. Książkiewicz

Abstract. In two Polish conservative flocks of Miniduck (K2) and Pekin (P33), registered by FAO as domestic genetic resources (World Watch List, 2000) the mean values of physical (tissue components) and qualitative traits of meat (pH15, pH24, colour of meat) were determined. The experimental flocks showed significant variations in body weight at 7 weeks of age (1540 vs 2088 in drakes and 1395 vs 1986 g in ducks), in the proportion of breast and leg muscles and skin with subcutaneous fat in eviscerated carcass. K2 ducks are characterized by outstanding musculature of breast and P33 ducks by that of lower leg and by low fatness. pH15 values of breast and leg muscles in K2 and P33 birds were greater than pH24 of these muscles. In both flocks pH15 values of 6.09 to 6.33 and pH24 values of 5.90 to 6.05 in breast muscles were lower than in leg muscles (6.33 to 6.46 and 6.12 to 6.37, respectively). A significantly lower L* value (darker colour) of breast muscle was characteristic of K2 birds (43.7 in males and 40.5 in females) compared to P33 males and females. Furthermore, breast muscles of K2 drakes and ducks had significantly higher redness (a*) and yellowness values (b*) than P33. In pectoralis superficialis muscle of K2 and P33 females, a significantly lower diameter was found for white muscle fibres (αW) (30.0 to 30.5 μm) and for red muscle fibres (βR) (16.9 to 17.6 μm) than in biceps femoris muscle (αW from 48.3 to 54.2; βR from 36.0 to 37.1 μm). Muscle fibres of K2 compared to P33 ducks were characterized by significantly greater diameters of βR muscle fibre in pectoralis superficialis muscle, and by lower αW and βR fibre diameters in biceps femoris muscle. The experiment showed that meat of ducks from the conservative flocks studied is valuable from the consumer’s point of view.


2020 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Gaku Kakehata ◽  
Yuta Goto ◽  
Shigeo Iso ◽  
Kazuyuki Kanosue

Medicine ◽  
2018 ◽  
Vol 97 (38) ◽  
pp. e12274 ◽  
Author(s):  
Jeong-Hyun Park ◽  
Kwang-Rak Park ◽  
Jinseo Yang ◽  
Gun-Hyun Park ◽  
Jaeho Cho

1996 ◽  
Vol 271 (1) ◽  
pp. H203-H211 ◽  
Author(s):  
H. Bitterman ◽  
V. Brod ◽  
G. Weisz ◽  
D. Kushnir ◽  
N. Bitterman

This study investigated mechanisms of the hemodynamic effects of oxygen in hemorrhagic shock induced by bleeding 30% of the total blood volume in anesthetized rats. An ultrasonic flowmeter was used to monitor regional blood flow. Changes in tissue perfusion were assessed by the laser-Doppler technique. The inhalation of 100% oxygen induced a significant increase in mean arterial blood pressure (MABP) and vascular resistance in the hindquarters, with a concomitant decrease in blood flow in the distal aorta and biceps femoris muscle. In contrast, oxygen did not change vascular resistance in the superior mesenteric artery (SMA) and renal beds and induced a significant increase in blood flow to the renal artery, SMA, and small bowel in hemorrhaged rats. L-Arginine (100 mg/kg iv) but not D-arginine or the vehicle (0.9% NaCl) completely abolished the effects of oxygen on blood pressure and reversed its effects on blood flow and resistance in the hindquarters and biceps femoris muscle. Administration of the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (50 mg/kg iv) significantly increased MABP and the resistance in the three vascular beds. Pretreatment of hemorrhaged rats with a superoxide dismutase mimic, the NO-stable radical 2,2,6,6-tetramethylpiperidine-N-oxyl (5 mg/kg iv), resulted in significantly diminished effects of oxygen on hindquarter hemodynamics. These results demonstrate a differential effect of oxygen, which increases vascular resistance in the hindquarters without a significant effect in the splanchnic and renal beds, thus favoring an increase in splanchnic and renal perfusion. It is suggested that inactivation of NO by reactive oxygen species may underlie the effects of oxygen on hindquarter vascular tone during shock.


1988 ◽  
Vol 17 (5) ◽  
pp. 269-277 ◽  
Author(s):  
DANIEL D. LEWIS ◽  
JAMIE R. BELLAH ◽  
M. DONALD McGAVIN ◽  
JACK M. GASKIN

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