Cat Dorsal Horn Research Articles

Depressant actions of methionine-enkephalin and somatostatin in cat dorsal horn neurones activated by noxious stimuli

Depressant actions of methionine-enkephalin and somatostatin in cat dorsal horn neurones activated by noxious stimuli

Selective reduction by noradrenaline and 5-hydroxytryptamine of nociceptive responses of cat dorsal horn neurones

Selective reduction by noradrenaline and 5-hydroxytryptamine of nociceptive responses of cat dorsal horn neurones

Chronic changes in the response of cells in adult cat dorsal horn following partial deafferentation; the appearance of responding cells in a previously non-responsive region : A.I. Basbaum and P.D. Wall, Brain Res., 116 (1976) 181–204

Chronic changes in the response of cells in adult cat dorsal horn following partial deafferentation; the appearance of responding cells in a previously non-responsive region : A.I. Basbaum and P.D. Wall, Brain Res., 116 (1976) 181–204

Staining of the dorsal root projection to the cat's dorsal horn by anterograde movement of horseradish peroxidase

A modification of the horseradish peroxidase method was used to stain selectively dorsal root fibers entering the spinal cord of the cat. This technique stains intact terminal arborizations. Using this method to examine the primary afferent supply to lamina II of the lumbosacral segments, we observed that both thick primary afferent collaterals (2–3 μm), entering by way of the dorsal column, and thinner primary afferent collaterals (<1 μm), entering by way of Lissauer's tract, form terminals in lamina II. The terminals derived from the thick primary afferent collaterals were concentrated in the ventral portion of lamina II.

Effect of substance P in cat dorsal horn neurones activated by noxious stimuli

Effect of substance P in cat dorsal horn neurones activated by noxious stimuli

Chronic changes in the response of cells in adult cat dorsal horn following partial deafferentation: The appearance of responding cells in a previously nonresponsive region

One side of the lumbar enlargement in adult cats was partially deafferented by cutting all dorsal roots caudal to L3 with the exception of the S1 dorsal root. At various times after the roots had been sectioned, the response of dorsal horn cells to natural and electrical stimuli applied to the leg and flank were recorded through extra-cellular glass microelectrodes. When animals were examined up to 24h after this partial deafferentation, no cells were located in a region between segments L4 and 5 which responded monosynaptically to cutaneous stimulation on the leg. By one week, cells began to appear in the L4-5 region which responded monosynaptically to peripheral stimuli. The numbers of these newly connected cells seemed to have stabilised by 1 month after the partial deafferentation, but the properties of these cells were abnormal in 6 ways. The location of the receptive field of the cells was characteristics either of the S1 dermatome or segments rostral to L4. Some cells had double receptive fields, one on the leg and one of the abdomen. The size of the receptive field varied more than is observed in normal intact dorsal horn. In particular, certain cells had unusually small recpetive fields with abrupt edges and no associated inhibitory fields. The cells receive less convergence from high threshold afferents than normally observed. Associated inhibitory fields were rarely encountered. Habituation was observed and in some cells with double receptive fields the response o onet are habituated while the response to the other area was unaffected. Slow wave recording on the surface of the cord showed that the effect of peripheral stimulation of the S1 dermatone spread far more extensively on the chronically deafferented side of the cord than it did on the intact side or in an intact cord. It was concluded that following partial deafferentation, the remaining afferents can establish connection with deafferented cells but the data presented did not allow a conclusion as to whether the new connections were produced by sprouting or by the unmasking of existing connections.

Effects of 5-hydroxytryptamine and bradykinin in cat dorsal horn neurones activated by noxious stimuli

Effects of 5-hydroxytryptamine and bradykinin in cat dorsal horn neurones activated by noxious stimuli

Correlation between extracellular focal potentials and K+ potentials evoked by primary afferent activity.

There is a clear, positive correlation in amplitude between changes in potassium potentials (deltaEK) and focal potentials (deltaV) evoked by tetanic stimulation of afferent nerves in the cuneate nucleus and dorsal horn of cats under Dial anaesthesia or after decerebration. Data obtained with stimulations at various frequencies and intensities, or recording at different positions give a relatively constant slope of deltaV/deltaEK (varying between 0.2 and 0.6 in different experiments). These observations are fully consistent with the possibility that deltaV mainly reflects changes in extracellular potassium concentration caused by the release of K+ from active terminals. Differences in time course of deltaEK ANd deltaV evoked by single stimuli are a steep function of distance and therefore can be ascribed to the slowness of diffusion, without excluding the possibility of an early additional depolarizing effect by another mechanism.

Ascending projections from marginal zone (Lamina I) neurons of the spinal dorsal horn

AbstractA search for postsynaptic elements, excited only by slowly‐conducting afferent fibers (Aδ and C), was made by recording from the dorsal horn of cats and monkeys with dye‐filled microelectrodes. Units identified by afferent responsiveness were tested for antidromic invasion by electrical stimulation of the opposite ventrolateral funiculus at the midcervical level. Recording points were marked by iontophoretically passing dye from the recording electrode and subsequently located in histologically‐prepared material. Evidence for antidromic excitation from spinal cord stimulation was found for five of 21 units in cat and 13 of 31 neurons in monkey. Antidromically excited cells were located within the distribution of the large posteromarginal neurons of the dorsal marginal zone (Lamina I). Although recording loci for a number of the elements studied were unequivocally located within Laminae II (substantia gelatinosa) or III, none could be antidromically excited. All antidromically driven units received a powerful input from Aδ primary afferent units and upon testing with natural stimuli responded specifically to stimuli of the type initiating activity either for high threshold mechanoreceptors or for low threshold thermoreceptors. It is concluded that some Lamina I neurons form part of an ascending projection which follows the spinal pathway of the spinothalamic tract and thereby contribute to the mechanical nociceptive and thermoreceptive features of this pathway. The absence of antidromic response is argued to be uncertain and evidence for a lack of projection is open to alternative explanation.

Erratum: Extracellular Accumulation of K+ Evoked by Activity of Primary Afferent Fibres in the Cuneate Nucleus and Dorsal Horn of Cats

Erratum: Extracellular Accumulation of K⁺ Evoked by Activity of Primary Afferent Fibres in the Cuneate Nucleus and Dorsal Horn of Cats

Somatotopic representation of hindlimb skin in cat dorsal horn.

Single-unit exploration of the dorsal horn of segments L4-S2 of unanesthetized cats with the neuraxis transected at lower thoracic levels reveals a somototopic organization in the horizontal plane. The dorsal horn dermatomes correspond closely to the dermatomes of the corresponding dorsal roots, and the ML gradient is equally well described by two different projection schemes: a distoproximal gradient and a ventrodorsal one (5, 33). There is no evidence of segmental discontinuity of the map. As is the case in other nuclear regions of the CNS, the relative area devoted to projections from the foot is disproportionately large relative to the area devoted to skin regions of similar size which are located more proximally on the limb. From our data, and from the close correspondence to anatomical data obtained by others, we suggest that at least some cutaneous afferent fibers from a given skin area project directly to any dorsal horn region where that skin area is represented. This assumption, together with the organization of the dorsal horn map, yields a model which predicts a precise somatotopic organization of presynaptic neuropil in the substantia gelatinosa.

Extracellular accumulation of K+ evoked by activity of primary afferent fibers in the cuneate nucleus and dorsal horn of cats.

K+-selective microelectrodes were used to measure extracellular K+ activity (aK) in the neuraxis of cats under Dial. In resting conditions, aK is stable (in range 2.0–3.0 mM) but may vary systematically with electrode position. Anoxia causes a progressive rise in aK, but only after a delay of 2–3 min and a maximum is not reached even after 15 min. Movements of the electrode are associated with transient increases in aK, presumably caused by tissue trauma. In areas rich in afferent terminals, direct stimulation through a microelectrode causes a sharp increase in aK, whose time course is consistent with diffusion from an instantaneous spherical source. Smaller increases in aK are produced by stimulating afferent fibers more peripherally, but definite changes can be recorded even with single pulses, and there is a cumulative, maintained rise in aK during repetitive stimulation at rates &gt; 0.5 s−1. Although the observed changes in aK fit reasonably a simple diffusion model at low frequencies (&lt; 5 s−1), a reuptake term (proportional to the change in aK) is necessary to obtain a satisfactory fit over a wide range of frequencies (1–200 s−1). The maximum aK reached during repetitive stimulation does not increase linearly with frequency, owing to a corresponding falling-off in K+ release per impulse.

The neurological mechanisms of pain. A review.

The neurological mechanisms of pain. A review.

Functional organization of the cat's dorsal horn: connectivity of myelinated fiber systems of hairy skin.

Functional organization of the cat's dorsal horn: connectivity of myelinated fiber systems of hairy skin.D N Tapper, P B Brown, and H MoraffD N Tapper, P B Brown, and H MoraffPublished Online:01 Sep 1973https://doi.org/10.1152/jn.1973.36.5.817MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByLocal Circuit Connections Between Hamster Laminae III and IV Dorsal Horn NeuronsStephen P. Schneider1 March 2008 | Journal of Neurophysiology, Vol. 99, No. 3Mechanosensory afferent input and neuronal firing properties in rodent spinal laminae III–V: re-examination of relationships with analysis of responses to static and time-varying stimuliBrain Research, Vol. 1034, No. 1-2Modulation of synaptic transmission from segmental afferents by spontaneous activity of dorsal horn spinal neurones in the cat12 August 2004 | The Journal of Physiology, Vol. 529, No. 2Tonic 5-HT modulation of spinal dorsal horn neuron activity evoked by both noxious and non-noxious stimuli: a source of neuronal plasticityPain, Vol. 40, No. 2A hypothesis on the physiological basis for causalgia and related painsPain, Vol. 24, No. 3Parallel processing of somatosensory information: A theoryBrain Research Reviews, Vol. 6, No. 1Innervation patterns of cutaneous hair receptors in catBrain Research, Vol. 249, No. 2The responses of dorsal horn neurones to controlled mechanical stimulation of the hindlimb skin in the rabbitBrain Research Reviews, Vol. 4, No. 1NociceptionBrain Research, Vol. 99, No. 2Spinal cord coding of graded nonnoxious and noxious temperature increasesExperimental Neurology, Vol. 48, No. 2Segmental and supraspinal actions on dorsal horn neurons responding to noxious and non-noxious skin stimuliPain, Vol. 1, No. 2Myelinated fiber types in the superficial radial nerve of the cat and their central projectionsBrain Research, Vol. 78, No. 1Afferent fibers with multiple encoding sitesBrain Research, Vol. 77, No. 2 More from this issue > Volume 36Issue 5September 1973Pages 817-26 https://doi.org/10.1152/jn.1973.36.5.817PubMed4805013History Published online 1 September 1973 Published in print 1 September 1973 Metrics

Functional organization of the cat's dorsal horn: spontaneous activity and central cell response to single impulses in single type I fibers.

Functional organization of the cat's dorsal horn: spontaneous activity and central cell response to single impulses in single type I fibers.P B Brown, H Moraff, and D N TapperP B Brown, H Moraff, and D N TapperPublished Online:01 Sep 1973https://doi.org/10.1152/jn.1973.36.5.827MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByMechanosensory afferent input and neuronal firing properties in rodent spinal laminae III–V: re-examination of relationships with analysis of responses to static and time-varying stimuliBrain Research, Vol. 1034, No. 1-2Interlimb reflex activity after spinal cord injury in man: strengthening response patterns are consistent with ongoing synaptic plasticityClinical Neurophysiology, Vol. 116, No. 1From innervation density to tactile acuityBrain Research, Vol. 1011, No. 1Effects of spinal and peripheral nerve lesions on the intersegmental synchronization of the spontaneous activity of dorsal horn neurons in the cat lumbosacral spinal cordNeuroscience Letters, Vol. 361, No. 1-3Synaptic transmission between single tactile and kinaesthetic sensory nerve fibers and their central target neuronesBehavioural Brain Research, Vol. 135, No. 1-2Modulation of synaptic transmission from segmental afferents by spontaneous activity of dorsal horn spinal neurones in the cat12 August 2004 | The Journal of Physiology, Vol. 529, No. 2Correlation of Peripheral Innervation Density and Dorsal Horn Map ScaleLei Wang, Ronald Millecchia, and Paul B. Brown1 August 1997 | Journal of Neurophysiology, Vol. 78, No. 2Tonic 5-HT modulation of spinal dorsal horn neuron activity evoked by both noxious and non-noxious stimuli: a source of neuronal plasticityPain, Vol. 40, No. 2Lack of spontaneous activity of cutaneous spinal dorsal horn neurons in awake, drug-free, spinally transected catsExperimental Neurology, Vol. 96, No. 2Electrical stimulation reveals relatively ineffective sural nerve projections to dorsal horn neurons in the catBrain Research, Vol. 371, No. 1Anatomical changes in cat dorsal horn cells after transection of a single dorsal rootExperimental Neurology, Vol. 64, No. 3The effect of dorsal column stimulation on the nociceptive response of dorsal horn cells and its relevance for pain suppressionPain, Vol. 4, No. Supp CGeneration of spike trains in CNS neuronsBrain Research, Vol. 84, No. 1Myelinated fiber types in the superficial radial nerve of the cat and their central projectionsBrain Research, Vol. 78, No. 1 More from this issue > Volume 36Issue 5September 1973Pages 827-39 https://doi.org/10.1152/jn.1973.36.5.827PubMed4375707History Published online 1 September 1973 Published in print 1 September 1973 Metrics

Effects of ketamine (CI 581) on cell responses to cutaneous stimulations in laminae IV and V in the cat's dorsal horn

The cells of laminae IV and V in the dorsal horn of the spinal cord are probably involved in the transmission of nociceptive messages to the upper centers. Pharmacological studies have shown that the analgesic proporties of some drugs could have their origin in the depression of synaptic transmission at this level. Therefore, the effect of ketamine on the activity of the laminae IV and V units was studied in spinal cats. Ketamine, 2–10 mg/kg, i.., did not modify significantly the spontaneous firing of the lamina IV cells, or their response to light cutaneous stimulations. Similarly, responses of the lamina V units to light stimulations (touch, hair movements, pressure) were not affected, while responses to nociceptive stimulations (pinching, strong electrical stimulation) were decreased. However, this effect is not sufficient to explain the whole analgesic action of ketamine and other sites of action must be found, sppecially at the subcortical and cortical levels.

Suppression of impulse transmission in the cat's dorsal horn by inhalation anesthetics.

Effects of halothane and nitrous oxide on impulse transmission through the dorsal horn were tested in deeerebnte cats. Unit discharge rates of dosral horn (lamina IV) neurons at rest and during maximal untunl stimulation (stroking of skin hairs) were recorded with extracellular microelectrodes. Halothane inhibited thae discharge rates in dose and time-related fahion, depressing spontanous activity slightly more and sooner than the response to tactile stimulalioa. Nitrous oxide had little effect on neuronal firing rates. These finding agree with earlier observations spind cats, and point to suppration of impulses of cutaneous origin in the dorsal horn as one means whereby general analhetics may obtund sensation.

Spinal neurons specifically excited by noxious or thermal stimuli: marginal zone of the dorsal horn.

HIGH-THRESHOLD MECHANORECEPTORS and their centrally projecting myelinated fibers make up a functionally distinct group of cutaneous sensory units that have been suggested as part of the afferent apparatus for pain resulting from mechanical damage to the skin (3, 17). The argument for their relation to pain was based on two points: 1) the ability of such afferent elements, unique among those with medullated fibers, to provide signals differentiating noxious from innocuous mechanical events affecting the skin; and 2) the well-established correlation between pain and activity in thin myelinated afferent fibers

Responses of dorsal horn cells of M. mulatta to cutaneous and sural nerve A and C fiber stimuli.

Responses of dorsal horn cells of M. mulatta to cutaneous and sural nerve A and C fiber stimuli.

Response of cat dorsal horn cells to variations of intensity, location, and area of cutaneous stimuli

The extracellular activity of cat dorsal horn cells was recorded. The stimulus consisted of a precisely controlled displacement of the clipped fur and skin of the ipsilateral hindlimb. The response to such a stimulus consisted of a transient onset discharge which was a function of hair movement and an adapting sustained discharge which was dependent on indentation of skin. The relation of the maintained discharge to the intensity of the stimulus, its location within the receptive field, and area of skin displaced by the probe was studied. Rate of firing was dependent on each of these three stimulus parameters. It was concluded that these cells would not be useful in signalling the precise location and intensity of cutaneous stimuli, but that they might serve as indicators of hair movement and total force delivered within the receptive field.