Changes in duodenal motility produced by noxious mechanical stimulation of the skin in rats

1976 ◽  
Vol 2 (4) ◽  
pp. 189-193 ◽  
Author(s):  
Yuko Sato ◽  
Naohito Terui
Keyword(s):  
Mechanical Stimulation ◽  
Duodenal Motility ◽  
Noxious Mechanical Stimulation ◽  
Stimulation Of

Convergence of heterotopic nociceptive information onto neurons of caudal medullary reticular formation in monkey (Macaca fascicularis)

1990 ◽  
Vol 63 (5) ◽  
pp. 1118-1127 ◽  
Author(s):  
L. Villanueva ◽  
K. D. Cliffer ◽  
L. S. Sorkin ◽  
D. Le Bars ◽  
W. D. Willis
Keyword(s):  
Electrical Stimulation ◽  
Reticular Formation ◽  
Mechanical Stimulation ◽  
Background Activity ◽  
The Body ◽  
Thermal Stimulation ◽  
Medullary Reticular Formation ◽  
Nociceptive Information ◽  
Noxious Mechanical Stimulation ◽  
Stimulation Of

1. Recordings were made in anesthetized monkeys from neurons in the medullary reticular formation (MRF) caudal to the obex. Responses of 19 MRF neurons to mechanical, thermal, and/or electrical stimulation were examined. MRF neurons exhibited convergence of nociceptive cutaneous inputs from widespread areas of the body and face. 2. MRF neurons exhibited low levels of background activity. Background activity increased after periods of intense cutaneous mechanical or thermal stimulation. Nearly all MRF neurons tested failed to respond to heterosensory stimuli (flashes, whistle sounds), and none responded to joint movements. 3. MRF neurons were excited by and encoded the intensity of noxious mechanical stimulation. Responses to stimuli on contralateral limbs were greater than those to stimuli on ipsilateral limbs. Responses were greater to stimuli on the forelimbs than to stimuli on the hindlimbs. 4. MRF neurons responded to noxious thermal stimulation (51 degrees C) of widespread areas of the body. Mean responses from stimulation at different locations were generally parallel to those for noxious mechanical stimulation. Responses increased with intensity of noxious thermal stimulation (45-50 degrees C). 5. MRF neurons responded with one or two peaks of activation to percutaneous electrical stimulation applied to the limbs, the face, or the tail. The differences in latency of responses to stimulating two locations along the tail suggested that activity was elicited by activation of peripheral fibers with a mean conduction velocity in the A delta range. Stimulation of the contralateral hindlimb elicited greater responses, with lower thresholds and shorter latencies, than did stimulation of the ipsilateral hindlimb. 6. Electrophysiological properties of monkey MRF neurons resembled those of neurons in the medullary subnucleus reticularis dorsalis (SRD) in the rat. Neurons in the caudal medullary reticular formation could play a role in processing nociceptive information. Convergence of nociceptive cutaneous input from widespread areas of the body suggests that MRF neurons may contribute to autonomic, affective, attentional, and/or sensory-motor processes related to pain.

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.

Processing of Nociceptive Mechanical and Thermal Information in Central Amygdala Neurons With Knee-Joint Input

2002 ◽  
Vol 87 (1) ◽  
pp. 103-112 ◽  
Author(s):  
Volker Neugebauer ◽  
Weidong Li
Keyword(s):  
Knee Joint ◽  
Mechanical Stimulation ◽  
Receptive Fields ◽  
Central Nucleus ◽  
Response Functions ◽  
Central Amygdala ◽  
Deep Tissue ◽  
Stimulus Response ◽  
Noxious Mechanical Stimulation ◽  
Stimulation Of

Pain has a strong emotional dimension, and the amygdala plays a key role in emotionality. The processing of nociceptive mechanical and thermal information was studied in individual neurons of the central nucleus of the amygdala, the target of the spino-parabrachio-amygdaloid pain pathway and a major output nucleus of the amygdala. This study is the first to characterize nociceptive amygdala neurons with input from deep tissue, particularly the knee joint. In 46 anesthetized rats, extracellular single-unit recordings were made from 119 central amygdala neurons that were activated orthodromically by electrical stimulation in the lateral pontine parabrachial area and were tested for receptive fields in the knee joints. Responses to brief mechanical stimulation of joints, muscles, and skin and to cutaneous thermal stimuli were recorded. Receptive-field sizes and thresholds were mapped and stimulus-response functions constructed. Neurons in the central nucleus of the amygdala with excitatory input from the knee joint ( n = 62) typically had large symmetrical receptive fields in both hindlimbs or in all four extremities and responded exclusively or preferentially to noxious mechanical stimulation of deep tissue ( n = 58). Noxious mechanical stimulation of the skin excited 30 of these neurons; noxious heat activated 21 neurons. Stimulus-response data were best fitted by a sigmoid nonlinear regression model rather than by a monotonically increasing linear function. Another 15 neurons were inhibited by noxious mechanical stimulation of the knee joint and other deep tissue. Fifteen neurons had no receptive field in the knee but responded to noxious stimulation of other body areas; 27 nonresponsive neurons were not activated by natural somesthetic stimulation. Our data suggest that excitation is the predominant effect of brief painful stimulation of somatic tissue on the population of central amygdala neurons with knee joint input. Their large symmetrical receptive fields and sigmoid rather than monotonically increasing linear stimulus-response functions suggest a role of nociceptive central amygdala neurons in other than sensory-discriminative aspects of pain.

Nociceptive responses of neurons in medial thalamus and their relationship to spinothalamic pathways

1978 ◽  
Vol 41 (6) ◽  
pp. 1592-1613 ◽  
Author(s):  
W. K. Dong ◽  
H. Ryu ◽  
I. H. Wagman
Keyword(s):  
Mechanical Stimulation ◽  
The Body ◽  
Direct Stimulation ◽  
Spinothalamic Tract ◽  
Medial Thalamus ◽  
C Fibers ◽  
Nociceptive Responses ◽  
C Fiber ◽  
Noxious Mechanical Stimulation ◽  
Stimulation Of

1. An extracellular study of the cat medial thalamus has revealed four types of somatosensory neurons. These were located primarily in the n. parafascicularis, n. subparafascicularis, and n. centralis lateralis; none were found in the n. centrum medianum. There was no functional segregation of neurons within each nucleus or between nuclei. Each type of neuron had large and often bilateral receptive areas. No somatotopic organization of neurons was found within the medial thalamus. 2. Noxious (N) and noxious-tap (NT) neurons comprising 72% of the sample (78 of 109 total) were considered to be nociceptive. N cells responded exclusively to noxious mechanical stimulation of skin, muscle fascia, tendons, and joints, and to direct stimulation of A-delta- and C-fiber groups in cutaneous, articular, and muscle nerves. NT cells responded to noxious and tap stimulation in a differential manner and to stimulation of the entire spectrum of A- and C-fibers. N and NT cells accurately signaled the duration of noxious mechanical stimulation. Their nociceptive responses were also graded as a function of both noxious stimulus intensity and the number of activated A-delta- and C-fibers. Stimulation of A- and C-fibers evoked, respectively, an inital burst and a late burst of discharges. A brief period of inhibition intervened between the initial and late bursts of NT cells. Prolonged afterdischarge was often observed following noxious natural stimulation or stimulation of A-delta- and C-fibers. The phenomenon of discharge "windup" was observed during iterative stimulation of C-fibers. 3. Tap (T) neurons (10%) responded only to brisk but innocuous taps applied to skin or underlying tissue. These cells were driven only by activation of A-alpha- and A-beta-fibers. The response to such stimulation was seen as an initial burst of discharges followed by an inhibitory period. 4. Inhibited (I) neurons (18%) had resting discharges that were inhibited by noxious stimuli and stimulation of A-beta- and C-fiber groups. 5. The results obtained from monitoring the peripherally evoked responses of nociceptive N and NT neurons before and after selective lesions of the spinal cord strongly suggested that the spinothalamic tracts were the only spinal projections mediating A- and C-fiber input to these cells. Each spinothalamic tract apparently carried information originating from both sides of the body.

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