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Kaczmarek D, Ristikankare J, Jankowska E. Does trans-spinal and local DC polarization affect presynaptic inhibition and post-activation depression? J Physiol 2017; 595:1743-1761. [PMID: 27891626 DOI: 10.1113/jp272902] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 11/15/2016] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS Trans-spinal polarization was recently introduced as a means to improve deficient spinal functions. However, only a few attempts have been made to examine the mechanisms underlying DC actions. We have now examined the effects of DC on two spinal modulatory systems, presynaptic inhibition and post-activation depression, considering whether they might weaken exaggerated spinal reflexes and enhance excessively weakened ones. Direct current effects were evoked by using local intraspinal DC application (0.3-0.4 μA) in deeply anaesthetized rats and were compared with the effects of trans-spinal polarization (0.8-1.0 mA). Effects of local intraspinal DC were found to be polarity dependent, as locally applied cathodal polarization enhanced presynaptic inhibition and post-activation depression, whereas anodal polarization weakened them. In contrast, both cathodal and anodal trans-spinal polarization facilitated them. The results suggest some common DC-sensitive mechanisms of presynaptic inhibition and post-activation depression, because both were facilitated or depressed by DC in parallel. ABSTRACT Direct current (DC) polarization has been demonstrated to alleviate the effects of various deficits in the operation of the central nervous system. However, the effects of trans-spinal DC stimulation (tsDCS) have been investigated less extensively than the effects of transcranial DC stimulation, and their cellular mechanisms have not been elucidated. The main objectives of this study were, therefore, to extend our previous analysis of DC effects on the excitability of primary afferents and synaptic transmission by examining the effects of DC on two spinal modulatory feedback systems, presynaptic inhibition and post-activation depression, in an anaesthetized rat preparation. Other objectives were to compare the effects of locally and trans-spinally applied DC (locDC and tsDCS). Local polarization at the sites of terminal branching of afferent fibres was found to induce polarity-dependent actions on presynaptic inhibition and post-activation depression, as cathodal locDC enhanced them and anodal locDC depressed them. In contrast, tsDCS modulated presynaptic inhibition and post-activation depression in a polarity-independent fashion because both cathodal and anodal tsDCS facilitated them. The results show that the local presynaptic actions of DC might counteract both excessively strong and excessively weak monosynaptic actions of group Ia and cutaneous afferents. However, they indicate that trans-spinally applied DC might counteract the exaggerated spinal reflexes but have an adverse effect on pathologically weakened spinal activity by additional presynaptic weakening. The results are also relevant for the analysis of the basic properties of presynaptic inhibition and post-activation depression because they indicate that some common DC-sensitive mechanisms contribute to them.
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Affiliation(s)
- D Kaczmarek
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden.,Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland.,Department of Biochemistry, Poznań University of Physical Education, Poznań, Poland
| | - J Ristikankare
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden
| | - E Jankowska
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Sweden
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Hayes HB, Chang YH, Hochman S. Stance-phase force on the opposite limb dictates swing-phase afferent presynaptic inhibition during locomotion. J Neurophysiol 2012; 107:3168-80. [PMID: 22442562 DOI: 10.1152/jn.01134.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Presynaptic inhibition is a powerful mechanism for selectively and dynamically gating sensory inputs entering the spinal cord. We investigated how hindlimb mechanics influence presynaptic inhibition during locomotion using pioneering approaches in an in vitro spinal cord-hindlimb preparation. We recorded lumbar dorsal root potentials to measure primary afferent depolarization-mediated presynaptic inhibition and compared their dependence on hindlimb endpoint forces, motor output, and joint kinematics. We found that stance-phase force on the opposite limb, particularly at toe contact, strongly influenced the magnitude and timing of afferent presynaptic inhibition in the swinging limb. Presynaptic inhibition increased in proportion to opposite limb force, as well as locomotor frequency. This form of presynaptic inhibition binds the sensorimotor states of the two limbs, adjusting sensory inflow to the swing limb based on forces generated by the stance limb. Functionally, it may serve to adjust swing-phase sensory transmission based on locomotor task, speed, and step-to-step environmental perturbations.
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Affiliation(s)
- Heather Brant Hayes
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
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Schmidt RF. Presynaptic inhibition in the vertebrate central nervous system. ERGEBNISSE DER PHYSIOLOGIE, BIOLOGISCHEN CHEMIE UND EXPERIMENTELLEN PHARMAKOLOGIE 2006; 63:20-101. [PMID: 4397694 DOI: 10.1007/bfb0047741] [Citation(s) in RCA: 177] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Baltina TV, Eremeev AA, Pleshchinskii IN. The state of the contralateral neuromotor apparatus of the rat in conditions of unilateral tenotomy. ACTA ACUST UNITED AC 2006; 36:385-9. [PMID: 16583166 DOI: 10.1007/s11055-006-0029-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Indexed: 11/26/2022]
Abstract
The effects of unilateral transection of the Achilles tendon (tenotomy) on the electromyographic characteristics of the gastrocnemius muscle on the contralateral side were studied in rats. Motor responses, reflex responses, and motor unit spike activity in the contralateral gastrocnemius muscle were studied in baseline conditions and on afferent stimulation before and 10 days after tenotomy. Changes in the nature of motor unit spike activity and responses to afferent stimulation were observed. The results obtained here demonstrate increases in the excitability of individual motoneurons in the contralateral motor center of the gastrocnemius muscle after exclusion of the symmetrical gastrocnemius muscle from the overall pattern of movement activity.
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Beloozerova IN, Rossignol S. Antidromic discharges in dorsal roots of decerebrate cats. II: studies during treadmill locomotion. Brain Res 2004; 996:227-36. [PMID: 14697500 DOI: 10.1016/j.brainres.2003.08.067] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In a previous companion paper [Brain Res. 846 (1999) 87-105] we have shown that the dorsal root activity of a decerebrate cat is composed of both orthodromic and antidromic discharges as determined by spike triggered averaging (STA). Furthermore we have shown that, during fictive locomotion in decerebrate and paralyzed cats, antidromic discharges peak in different parts of locomotion cycle but mainly in the flexion phase. In the present study, we have recorded unit potentials from dorsal rootlets during treadmill locomotion in order to understand better the role of movement-related feedback in the generation of antidromic potentials. The unitary activity of 92 antidromically discharging units was recorded in proximal stumps of cut dorsal roots, and that of 20 such units was recorded in uncut roots using two bipolar Ag/AgCl electrodes in both cases. The activity of 80% (74/92) units in cut filaments and of 70% (14/20) units in uncut ones was phasewise related to stepping movements. The peaks of activity of different units occurred during different phases of the step cycle both in cut and uncut filaments. In most cases, the peak of activity was superimposed upon a background of sustained discharge. After blocking the orthodromic flow in a filament (local anesthesia or distal section), the antidromic discharges continued to peak during the same phase but the rate of the discharges increased. We conclude that movement-related afferent feedback significantly modulates the antidromic discharges in dorsal roots during treadmill locomotion. We suggest that these antidromic discharges have a role in controlling afferent feedback during movement.
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Affiliation(s)
- Irina N Beloozerova
- Faculté de Médecine, Centre de recherche en sciences Neurologiques, Université de Montréal, Pavillon Desmarais, Montreal, Quebec, Canada H3T 1J4
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ECCLES RM, HOLMQVIST B, VOORHOEVE PE. PRESYNAPTIC INHIBITION FROM CONTRALATERAL CUTANEOUS AFFERENT FIBRES. ACTA ACUST UNITED AC 1996; 62:464-73. [PMID: 14252581 DOI: 10.1111/j.1748-1716.1964.tb10444.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Feria M, Abreu P, Abad F, Sánchez A. Relationship between autotomy behaviour and spinal cord monoaminergic levels in rats. Pain 1992; 48:429-437. [PMID: 1375723 DOI: 10.1016/0304-3959(92)90096-t] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In the rat, unilateral neurectomy of the sciatic and saphenous nerves causes autotomy, a self-mutilation behaviour, against the denervated limb that is variable in both its onset and severity. To study some of the possible neurochemical sources of this variability, spinal cord levels of norepinephrine (NE), dopamine (DA), serotonin (5-HT0 and 5-hydroxyindoleacetic acid (5-HIAA) were analysed ipsi- and contralateral to the lesioned side by high performance liquid chromatography at C5-T1 and L1-S1. According to the early or late onset and to the slight or intense autotomy behaviour, the animals were assigned to four different groups: early autotomy, early no autotomy, late autotomy, and late no autotomy. Two sham-operated groups were sacrificed at an early or late stage in the postoperative period. The spinal cord NE content remained unchanged throughout the different experimental situations. The more conspicuous changes observed were: (1) a generalized increase in spinal 5-HT metabolism in all deafferented groups; (2) a significant and selective increase in lumbosacral 5-HT and 5-HIAA levels of the rats that did not self-lesion for 8 weeks after deafferentation and (3) a significant fall (30-45%) in DA levels at denervated spinal segments of the rats that actively self-attacked late in the postoperative period. The data suggests that spinal cord serotonergic and dopaminergic influences play an important role in determining the susceptibility to autotomy (and perhaps chronic pain) after peripheral deafferentation.
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Affiliation(s)
- Manuel Feria
- Department of Pharmacology, Faculty of Medicine, University of La Laguna, TenerifeSpain Department of Physiology, Faculty of Medicine, University of La Laguna, TenerifeSpain
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Gossard JP, Rossignol S. Phase-dependent modulation of dorsal root potentials evoked by peripheral nerve stimulation during fictive locomotion in the cat. Brain Res 1990; 537:1-13. [PMID: 2085765 DOI: 10.1016/0006-8993(90)90333-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
To help elucidate the role of presynaptic mechanisms in the control of locomotor movements, the transmission of PAD pathways was investigated by recording dorsal root potentials (DRPs) evoked by electrical stimulation of cutaneous and muscle nerves of both hindlimbs at various phases of the fictive step cycle. Fictive locomotion occurred spontaneously in decorticate cats or by stimulating the mesencephalic locomotor region (MLR) as well as in low spinal cats injected with nialamide and L-DOPA. Evoked DRPs were superimposed on a fluctuating DRP accompanying the fictive locomotor rhythm (locomotor DRP) which typically consisted of two peaks of depolarization per cycle, the largest peak occurring during the flexor phase. The amplitude of evoked DRPs was substantially modulated throughout the locomotor cycle and followed a similar modulation pattern for all stimulated nerves whether ipsilateral (i-) or contralateral (co-). The amplitude of evoked DRPs decreased at the beginning of the flexor phase, dropped to a minimum later in the flexor phase and then increased during the extensor phase where it became maximum. Results were comparable in decorticate and spinal preparations and for L6 and L7 rootlets with cutaneous and muscle nerve stimulation. It is noteworthy that the modulation pattern for a given rootlet was similar for i- and co- stimulation, even though the bilateral locomotor DRPs fluctuate out-of-phase with each other, subjecting the stimulated fibres to opposite presynaptic polarization changes. This suggests that the modulation may depend more on the presynaptic mechanisms of the receiving fibres than on those of the stimulated fibres. These results demonstrate that the transmission in spinal pathways involved in primary afferent depolarization (PAD) is phasically modulated by the activity in the spinal locomotor network. It is further suggested that the presynaptic inhibition associated with PAD evoked by movement-related sensory feedback during real locomotion could be modulated in a similar way.
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Affiliation(s)
- J P Gossard
- Centre de Recherche en Sciences Neurologiques, Faculté de Médecine, Université de Montréal, Que., Canada
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9
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Menéndez JA, Cubas SC. Changes in contralateral protein metabolism following unilateral sciatic nerve section. JOURNAL OF NEUROBIOLOGY 1990; 21:303-12. [PMID: 1689770 DOI: 10.1002/neu.480210206] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Changes in nerve biochemistry, anatomy, and function following injuries to the contralateral nerve have been repeatedly reported, though their significance is unknown. The most likely mechanisms for their development are either substances carried by axoplasmic flow or electrically transmitted signals. This study analyzes which mechanism underlies the development of a contralateral change in protein metabolism. The incorporation of labelled amino acids (AA) into proteins of both sciatic nerves was assessed by liquid scintillation after an unilateral section. AA were offered locally for 30 min to the distal stump of the sectioned nerves and at homologous levels of the intact contralateral nerves. At various times, from 1 to 24 h, both sciatic nerves were removed and the proteins extracted with trichloroacetic acid (TCA). An increase in incorporation was found in both nerves 14-24 h after section. No difference existed between sectioned and intact nerves, which is consistent with the contralateral effect. Lidocaine, but not colchicine, when applied previously to the nerves midway between the sectioning site and the spinal cord, inhibited the contralateral increase in AA incorporation. It is concluded that electrical signals, crossing through the spinal cord, are responsible for the development of the contralateral effect. Both the nature of the proteins and the significance of the contralateral effect are matters for speculation.
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Affiliation(s)
- J A Menéndez
- División Biofísica, Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
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10
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Lundberg A, Malmgren K, Schomburg ED. Reflex pathways from group II muscle afferents. 3. Secondary spindle afferents and the FRA: a new hypothesis. Exp Brain Res 1987; 65:294-306. [PMID: 3556458 DOI: 10.1007/bf00236301] [Citation(s) in RCA: 238] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A hypothesis is forwarded regarding the role of secondary spindle afferents and the FRA (flexor reflex afferents) in motor control. The hypothesis is based on evidence (cf. Lundberg et al. 1987a, b) summarized in 9 introductory paragraphs. Group II excitation. It is postulated that subsets of excitatory group II interneurones (transmitting disynaptic group II excitation to motoneurones) may be used by the brain to mediate motor commands. It is assumed that the brain selects subsets of interneurones with convergence of secondary afferents from muscles whose activity is required for the movement. During movements depending on coactivation of static gamma-motoneurones impulses in secondary afferents may servo-control transmission to alpha-motoneurones at an interneuronal level. The large group II unitary EPSPs in interneurones are taken to indicate that, given an adequate interneuronal excitability, impulses in single secondary afferents may fire the interneurone and produce EPSPs in motoneurones; interneuronal transmission would then be equivalent to that in a monosynaptic pathway but with impulses from different muscles combining into one line. It is postulated that impulses in the FRA are evoked by the active movements and that the role of the multisensory convergence from the FRA onto the group II interneurones is to provide the high background excitability which allows the secondary spindle afferents to operate as outlined above. The working hypothesis is put forward that a movement governed by the excitatory group II interneurones is initiated by descending activation of these interneurones, but is maintained in a later phase by the combined effect of FRA activity evoked by the movement and by spindle secondaries activated by descending activation of static gamma-motoneurones. As in the original "follow up length servo" hypothesis (Rossi 1927; Merton 1953), we assume that a movement at least in a certain phase can be governed from the brain solely or mainly via static gamma-motoneurones. However, our hypothesis implies that the excitatory group II reflex connexions have a strength which does not allow transmission to motoneurones at rest and that the increase in the gain of transmission during an active movement is supplied by the movement itself. Group II inhibition. It is suggested that the inhibitory reflex pathways like the excitatory ones have subsets of interneurones with limited group II convergence. When higher centres utilize a subset of excitatory group II interneurones to evoke a given movement, there may mobilize inhibitory subsets to inhibit muscles not required in the movement.(ABSTRACT TRUNCATED AT 400 WORDS)
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Wójcik G, Lupa K, Niechaj A. Differential decerebrate control of depolarization in the central terminals of cutaneous afferents in the sacral cord. Brain Res 1983; 266:233-41. [PMID: 6871661 DOI: 10.1016/0006-8993(83)90654-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Presynaptic depolarization of cutaneous afferents has been investigated in the sacral cord of decerebrate cats before and after spinal cord transection. In the decerebrate state the central terminals of caudal femoral cutaneous nerve are depolarized by ipsilateral volleys entering the cord via sacral and lumbar dorsal roots. A significant increase of depolarization occurring after severing the cord indicates that there is tonic decerebrate inhibition of presynaptic depolarization in terminals of caudal femoral cutaneous nerve. In contrast to this finding, presynaptic depolarization evoked in the central terminals of the pudendal nerve by ipsilateral volleys entering the cord through sacral and lumbar dorsal roots is not subjected to decerebrate inhibitory control. It is suggested that differential inhibitory control of depolarization in the central terminals of cutaneous nerves in the sacral cord is related to the intraspinal course of their fibres, to differences in the receptor types involved, and to the location of their innervation fields. In more than half of the decerebrate preparations stimulation of the central terminals of cutaneous afferents through microelectrodes evokes antidromic spikes appearing simultaneously in ipsi- and contralateral nerves. The time course of bilateral excitability changes is similar on both sides of the cord. It is assumed that presynaptic effects are transmitted to the contralateral side by collaterals of ipsilateral cutaneous afferents.
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12
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Marlinskii VV. Primary afferent depolarization in the spinal cord mechanisms and functions. NEUROPHYSIOLOGY+ 1983. [DOI: 10.1007/bf01073223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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13
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Gerren RA, Luttges MW. Functional changes in undamaged sciatic nerves and spinal cord of mice following nerve damage. Exp Neurol 1979; 65:587-607. [PMID: 467561 DOI: 10.1016/0014-4886(79)90046-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Lupa K, Wójcik G, Ozóg M, Niechaj A. Spread of the dorsal root potentials in lower lumbar, sacral and upper caudal spinal cord. Pflugers Arch 1979; 381:201-7. [PMID: 229464 DOI: 10.1007/bf00583250] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
Bilateral dorsal root potentials (DRPs) evoked in the S3 dorsal roots by stimulation of the S2 and L6 dorsal roots and the cutaneous afferents entering the spinal cord in the lumbar segments have been studied in spinal cats. Stimulation of all these afferents produces DRPs which have the same amplitude on both sides of the spinal cord. During long-lasting repetitive stimulation the negativity of the ipsilateral dorsal root is maintained only when this stimulation is applied to the neighbouring dorsal root. Depression of the testing DRPs produced by preceding single volleys or repetitive stimulation is only slightly larger on the contralateral side of the cord. The difference between depression of the DRPs on both sides of the cord is significantly smaller in the S3 than in the L7 segment. Following conditioning tetanization both ipsi- and contralateral DRPs undergo depression. The pattern of bilateral DRPs in the S3 segment significantly differs from that observed in the L7 segment and these differences correspond to the already known distinct arrangement of the substantia gelatinosa in the two parts of the cord.
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Holobut W, Niechaj A. The dorsal root potentials produced on both sides of the spinal cord by long-lasting stimulation of the cutaneous afferents. J Physiol 1973; 230:15-27. [PMID: 4702418 PMCID: PMC1350383 DOI: 10.1113/jphysiol.1973.sp010172] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
1. The dorsal root potentials (DRPs) produced on both sides of the spinal cord by prolonged repetitive stimulation of the alpha cutaneous afferents have been studied in spinal cats lightly anaesthetized by barbiturate.2. Ipsilateral depolarization produced by long-lasting stimulation increases rapidly to maximum and then, in spite of a slight decline, it persists throughout the period of stimulation. Contralateral depolarization after its increase to maximum rapidly subsides to zero during continued stimulation.3. Depression of the contralateral DRP during long-lasting stimulation depends on its frequency. It occurs at higher frequencies of tetanization (in excess of 20 c/s) while at low frequencies (3-15 c/s) contralateral DRP is maintained till the end of stimulation, displaying the pattern similar to depolarization of the ipsilateral dorsal root.4. The effect of temporal facilitation on the DRPs is much greater and of longer duration on the contralateral than on ipsilateral side of the spinal cord.5. After long-lasting conditioning stimulation there is prolonged depression of the testing DRPs produced by a single volley in the same nerve, Since duration of this depression is prolonged beyond the known duration of presynaptic inhibitory action, it is suggested to be due to homosynaptic depression in interneuronal pathways producing primary afferent depolarization.6. More severe and prolonged depression of the contralateral DRPs evoked by preceding volleys indicates enhancement of homosynaptic depression on the other side of the spinal cord. It may be assumed that this increase depends on greater complexity of synaptic organization of the pathways producing contralateral depolarization of the primary afferent fibres.
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Sato M, Takagi H. Effect of morphine on the pre- and postsynaptic inhibitions in the spinal cord. Eur J Pharmacol 1971; 14:150-4. [PMID: 5164251 DOI: 10.1016/0014-2999(71)90208-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Jänig W, Zimmermann M. Presynaptic depolarization of myelinated afferent fibres evoked by stimulation of cutaneous C fibres. J Physiol 1971; 214:29-50. [PMID: 5575364 PMCID: PMC1331820 DOI: 10.1113/jphysiol.1971.sp009417] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
1. The origin of the dorsal root potential observed following a volley in cutaneous unmyelinated or C fibres (C-DRP) has been investigated by several assays.2. Measurements of the spatial decrement of the C-DRP along the dorsal roots indicate that mainly the thick myelinated primary afferent fibres contribute to this C-DRP.3. The spatial configuration of the intraspinal potential field during the course of the C-DRP is similar to that of the field correlated to the A-DRP, i.e. the DRP evoked by a volley in the A fibres of the same cutaneous nerve. It is concluded therefrom that both A- and C-DRPs signal presynaptic depolarizations of afferent fibres in the same regions of the dorsal horn.4. Intrafibre recordings reveal that C input produces primary afferent depolarization (C-PAD) mainly in cutaneous and articular afferents, but not in muscle Group Ia afferents.5. These findings and direct measurements of the interactions between A- and C-DRPs indicate that the pathways involved in A- and C-PAD exhibit convergence.6. C-DRPs were also recorded from contralateral rootlets.7. Some functional aspects of the PAD produced by an afferent volley in C fibres are discussed.
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Jankowska E, Jukes MG, Lund S, Lundberg A. The effect of DOPA on the spinal cord. 5. Reciprocal organization of pathways transmitting excitatory action to alpha motoneurones of flexors and extensors. ACTA PHYSIOLOGICA SCANDINAVICA 1967; 70:369-88. [PMID: 4293473 DOI: 10.1111/j.1748-1716.1967.tb03636.x] [Citation(s) in RCA: 323] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Schmidt RF, Senges J, Zimmermann M. Presynaptic depolarization of cutaneous mechanoreceptor afferents after mechanical skin stimulation. Exp Brain Res 1967; 3:234-47. [PMID: 6030824 DOI: 10.1007/bf00235587] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Jankowska E, Lund S, Lundberg A. The Effect of DOPA on the Spinal Cord 4. Depolarization Evoked in the Central Terminals of Contralateral Ia Afferent Terminals by Volleys in the Flexor Reflex Aflerents. ACTA ACUST UNITED AC 1966. [DOI: 10.1111/j.1748-1716.1966.tb03434.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hongo T, Jankowska E, Lundberg A. Convergence of excitatory and inhibitory action on interneurones in the lumbosacral cord. Exp Brain Res 1966; 1:338-58. [PMID: 5922514 DOI: 10.1007/bf00237706] [Citation(s) in RCA: 90] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Devanandan MS, Eccles RM, Yokota T. Depolarization of afferent terminals evoked by muscle stretch. J Physiol 1965; 179:417-29. [PMID: 5858622 PMCID: PMC1357336 DOI: 10.1113/jphysiol.1965.sp007670] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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DEVANANDAN MS, HOLMQVIST B, YOKOTA T. Presynaptic Depolarization of Group I Muscle Afferents by Gontralateral Afferent Volleys. ACTA ACUST UNITED AC 1965; 63:46-54. [PMID: 14286773 DOI: 10.1111/j.1748-1716.1965.tb04040.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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