scholarly journals Actions on gamma-motoneurones elicited by electrical stimulation of group III muscle afferent fibres in the hind limb of the cat.

1983 ◽  
Vol 335 (1) ◽  
pp. 275-292 ◽  
Author(s):  
B Appelberg ◽  
M Hulliger ◽  
H Johansson ◽  
P Sojka
Keyword(s):  
Electrical Stimulation ◽  
Hind Limb ◽  
Group Iii ◽  
Gamma Motoneurones ◽  
Muscle Afferent ◽  
Muscle Afferent Fibres ◽  
Stimulation Of

Spinoreticular neurons that receive group III input are inhibited by MLR stimulation

2002 ◽  
Vol 93 (1) ◽  
pp. 92-98 ◽  
Author(s):  
Alexandr M. Degtyarenko ◽  
Marc P. Kaufman
Keyword(s):  
Electrical Stimulation ◽  
Tibial Nerve ◽  
Afferent Input ◽  
Ventrolateral Medulla ◽  
Central Command ◽  
Mesencephalic Locomotor Region ◽  
Group Iii ◽  
Tibial Nerve Stimulation ◽  
Muscle Afferent ◽  
Stimulation Of

In decerebrate paralyzed cats, we examined the responses of 18 spinoreticular neurons to electrical stimulation of the mesencephalic locomotor region. The activity of each of the spinoreticular neurons was recorded extracellularly from laminae IV through VI of the L7 and S1 spinal cord. In addition, each of the 18 spinoreticular neurons received group III afferent input from the tibial nerve. Spinoreticular projections were established for each of 18 neurons by antidromic invasion of the ventro lateral medulla at the P11 though P14 levels. The onset latencies and current thresholds for antidromic invasion from the ventro lateral medulla averaged 15.0 ± 3.8 ms and 117 ± 11 μA, respectively. Electrical stimulation of the mesencephalic locomotor region attenuated the spontaneous activity or the responses of each of the spinoreticular neurons to tibial nerve stimulation at currents that recruited group III afferents. Our data support the notion that thin-fiber muscle afferent input to the ventrolateral medulla is gated by a central command to exercise.

Central command, but not muscle reflex, stimulates cutaneous sympathetic efferents of cats

1998 ◽  
Vol 274 (5) ◽  
pp. H1552-H1559 ◽  
Author(s):  
Janeen M. Hill ◽  
Marc P. Kaufman
Keyword(s):  
Electrical Stimulation ◽  
Blocking Agent ◽  
Muscle Afferents ◽  
Group Iii ◽  
Hairy Skin ◽  
Sympathetic Efferents ◽  
Muscle Reflex ◽  
Decerebrate Cats ◽  
Sympathetic Discharge ◽  
Stimulation Of

We determined the effects of stimulation of the mesencephalic locomotor region (MLR) and the muscle reflex, each evoked separately, on the discharge of cutaneous sympathetic fibers innervating the hairy skin of decerebrate cats. Electrical stimulation of the MLR was performed while the cats were paralyzed with vecuronium bromide. The muscle reflex was evoked while the cats were not paralyzed by electrical stimulation of the tibial nerve at current intensities that did not activate directly group III and IV muscle afferents. MLR stimulation increased, on average, the discharge of the 23 cutaneous sympathetic fibers tested ( P < 0.05). The muscle reflex, in contrast, had no overall effect on the discharge of 21 sympathetic fibers tested ( P > 0.05). Both maneuvers markedly increased mean arterial pressure and heart rate ( P < 0.05). Prevention of the baroreceptor reflex with the α-adrenergic blocking agent phentolamine did not reveal a stimulatory effect of the muscle reflex on cutaneous sympathetic discharge. We conclude that the MLR is a more important mechanism than is the muscle reflex in controlling sympathetic discharge to hairy skin during dynamic exercise.

Responses of neurons in VPL and VPL-VL region of the cat to algesic stimulation of muscle and tendon

1983 ◽  
Vol 49 (3) ◽  
pp. 649-661 ◽  
Author(s):  
K. D. Kniffki ◽  
K. Mizumura
Keyword(s):  
Electrical Stimulation ◽  
Mechanical Stimulation ◽  
Receptive Fields ◽  
Transitional Zone ◽  
The Other ◽  
Group Iii ◽  
Group I ◽  
Nociceptive Information ◽  
Noxious Mechanical Stimulation ◽  
Stimulation Of

1. The responses evoked by electrical stimulation of cutaneous and muscle nerves, by noxious and innocuous mechanical stimulation of muscle, tendon, and cutaneous tissues, and by intra-arterial (ia) injection of algesic substances (potassium, bradykinin) into arteries supplying the gastrocnemius-soleus muscle (GS) were studied in single neurons located in the ventroposterolateral nucleus (VPL) and in the transitional zone between VPL and the ventrolateral nucleus (VL) of cats lightly anesthetized with thiopenthal. Such chemical stimulation of the muscles has been shown to activate muscular groups III and IV axons specifically (43, 44) and presumably is nociceptive in character (14, 17, 31). 2. One hundred eight neurons were tested. Eighty-three of the units responded only to various types of cutaneous stimulation of the hindlimb. The other 25 responded to algesic stimulation of muscle and/or tendon. Of these latter 25, 7 had no apparent cutaneous receptive field although 4 of them responded to electrical stimulation of the common peroneal and/or sural nerve. Thus, only three neurons responded exclusively to algesic chemical and noxious mechanical stimulation of the muscle. Of the other 18 neurons, 14 had cutaneous receptive fields restricted to the hindlimb and often responded to non-noxious repetitive light stroking and to noxious pinching with a high-frequency discharge. Four cells (two of which had cutaneous input only from low-threshold mechanoreceptors) had complex and large receptive fields extending to more than one limb. 3. Potassium was a more potent muscle receptor stimulant than bradykinin, the latter only weakly exciting 3 neurons of 24 tested with both substances. The responses to potassium were rapid (approximately 4.0 s in latency) and tended to be greater (have higher response rates) for the units that responded to cutaneous as well as muscle/tendon stimulation. 4. Most neurons that responded to noxious deep stimulation had a threshold for the GS nerve volley in the group III fiber range. The few neurons with thresholds slightly below the group III range did not respond to activation of group I or II muscle spindle afferents by intra-arterial application of succinylcholine or by stretching the muscle. 5. Neurons with responses to any of the muscle, tendon, or cutaneous nociceptive stimuli were located at the ventral and dorsal periphery of VPL and in the VPL-VL transitional zone. 6. These results strongly suggest that there exist regions within the lateral diencephalon of cats that are capable of processing nociceptive information and that these regions are located at the periphery of VPL.

Group III muscle afferents evoke reflex depressor responses to repetitive muscle contractions in rabbits

2000 ◽  
Vol 278 (3) ◽  
pp. H871-H877 ◽  
Author(s):  
J. M. Legramante ◽  
G. Raimondi ◽  
C. M. Adreani ◽  
S. Sacco ◽  
F. Iellamo ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Arterial Pressure ◽  
Pressor Response ◽  
Muscle Afferents ◽  
Triceps Surae ◽  
Muscle Twitch ◽  
Group Iii ◽  
Twitch Contraction ◽  
Depressor Response ◽  
Stimulation Of

Repetitive-twitch contraction of the hindlimb muscles in anesthetized rabbits consistently evokes a reflex depressor response, whereas this type of contraction in anesthetized cats evokes a reflex pressor response in about one-half of the preparations tested. Rapidly conducting group III fibers appear to comprise the afferent arm of the reflex arc, evoking the depressor response to twitch contraction in rabbits because electrical stimulation of their axons reflexly decreases arterial pressure. In contrast, electrical stimulation of the axons of slowly conducting group III and group IV afferents reflexly increases arterial pressure in rabbits. In the present study, we examined the discharge properties of group III and IV muscle afferents and found that the former (i.e., 13 of 20), but not the latter (i.e., 0 of 10), were stimulated by 5 min of repetitive-twitch contraction (1 Hz) of the rabbit triceps surae muscles. Moreover, most of the group III afferents responding to contraction appeared to be mechanically sensitive, discharging in synchrony with the muscle twitch. On average, rapidly conducting group III afferents responded for the 5-min duration of 1-Hz repetitive-twitch contraction, whereas slowly conducting group III afferents responded only for the first 2 min of contraction. We conclude that rapidly conducting group III afferents, which are mechanically sensitive, are primarily responsible for evoking the reflex depressor response to repetitive-twitch contractions in anesthetized rabbits.

Responses of neurons in feline trigeminal subnucleus caudalis (medullary dorsal horn) to cutaneous, intraoral, and muscle afferent stimuli

1986 ◽  
Vol 55 (2) ◽  
pp. 227-243 ◽  
Author(s):  
N. Amano ◽  
J. W. Hu ◽  
B. J. Sessle
Keyword(s):  
Electrical Stimulation ◽  
Receptive Field ◽  
Neuronal Population ◽  
Afferent Stimulation ◽  
Nociceptive Neurons ◽  
Medullary Dorsal Horn ◽  
Tongue Muscles ◽  
Muscle Afferent ◽  
Afferent Inputs ◽  
Stimulation Of

The extracellular activity of single neurons was recorded in subnucleus caudalis (medullary dorsal horn) of chloralose-anesthetized cats to test the effects of electrical and natural stimuli that activated afferents supplying the jaw and tongue muscles as well as the face, teeth, and intraoral mucosa. Many caudalis neurons that could be functionally classified on the basis of their cutaneous receptive-field properties as low-threshold mechanoreceptive (LTM), wide-dynamic-range (WDR), or nociceptive-specific (NS) neurons could be excited by muscle afferent stimuli. Only five neurons were encountered that received muscle afferent inputs and had no demonstrable cutaneous, dental, or mucosal input. The muscle afferent inputs were a particular feature of the cutaneous nociceptive (i.e., WDR and NS) neurons. Approximately two-thirds of this nociceptive neuronal population (n = 109) could be excited by jaw and/or tongue muscle stimulation, whereas only a small proportion of the LTM neuronal population (n = 247) was activated by muscle afferent stimulation. Neurons with a demonstrated direct axonal projection to the contralateral thalamus as well as nonprojection neurons received muscle afferent inputs. The caudalis nociceptive neurons receiving muscle as well as cutaneous afferent inputs had receptive-field properties comparable to those previously described for caudalis cutaneous nociceptive neurons; they were predominantly located in laminae I/II and V/VI, and many also received convergence of tooth pulp afferent inputs. These neurons generally had larger cutaneous receptive fields than neurons unresponsive to muscle afferent stimulation. The muscle afferent inputs were considered to be predominantly of a nociceptive character for several reasons. These included the long latency and high threshold of most neuronal responses evoked by electrical stimulation of the muscle afferents, the predominance of afferents of small diameter in some of the muscle nerves stimulated, the preferential responsiveness to the muscle afferent stimulation of neurons that were functionally identified as cutaneous nociceptive neurons, and the responsiveness of most of the neurons excited by electrical stimulation of the muscle nerves also to noxious mechanical or thermal stimulation of muscle and the injection of two or more algesic chemicals into small arteries supplying the jaw and tongue muscles. Of the algesic chemicals used in this study (7% NaCl, KCl, bradykinin, histamine, 5-HT), the first two were found to be the most effective and to cause the most rapidly induced excitation.(ABSTRACT TRUNCATED AT 400 WORDS)

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