1. Fast excitatory postsynaptic potentials (EPSPs) evoked by stimulation of A delta and C fibres were examined intracellular recording from substantia gelatinosa (SG) neurones in a transverse slice preparation adult rat spinal cord. 2. Single low‐intensity stimuli applied to the dorsal root activated monosynaptic EPSPs 70% SG neurones. In 5% neurones, increasing intensity duration solely fibre‐mediated EPSPs. About 20% received both fibre input primary afferents. 3. Low concentrations...

1. Primary afferent fiber-evoked synaptic responses and the mechanisms of spike slow potential generation have been examined in adult rat substantia gelatinosa (SG) neurons an vitro transverse spinal cord slice preparation which attached dorsal root is retained. Intracellular recordings were made from SG identified by morphological electrophysiological criteria. Afferent fast excitatory postsynaptic potentials (fast EPSPs) EPSPs analyzed. 2. had mean resting membrane -67.1 +/- 0.5 mV (mean...

Intracellular recordings were made from substantia gelatinosa (s.g.) neurones in slices cut adult rat spinal cord and maintained vitro. Noradrenaline applied by superfusion (1-50 microM), or brief pressure ejection a micropipette, reversibly hyperpolarized 80% of the s.g. cells. The noradrenaline induced hyperpolarization was associated with an increase conductance it reversed polarity at -88 mV. reversal potential changed when external potassium concentration changed, as predicted Nernst...

1. The actions of opioid receptor agonists on synaptic transmission in substantia gelatinosa (SG) neurones adult (6- to 10-week-old) rat spinal cord slices were examined by use the blind whole-cell patch-clamp technique. 2. Both mu-receptor agonist DAMGO (1 microM) and delta-receptor DPDPE reduced amplitude glutamatergic excitatory postsynaptic currents (EPSCs) which monosynaptically evoked stimulating Adelta afferent fibres. also decreased frequency miniature EPSCs without affecting their...

1. The possible roles of glycine and gamma‐aminobutyric acid (GABA) as inhibitory transmitters in the spinal dorsal horn were studied by intracellular recordings from substantia gelatinosa (SG) neurones transverse slices adult rat cord which retained an attached root. 2. Stimulation primary afferent A delta fibres evoked initial excitatory postsynaptic potential (fast EPSP) followed a short and/or long (short IPSP). IPSP, observed twenty‐nine SG (37%) received inputs, had mean latency 3.6 ms...

Although intrathecal administration of norepinephrine is known to produce analgesia, cellular mechanisms for this action have not yet been fully understood.The actions (50 microm) on glutamatergic transmission were examined by using the whole cell patch clamp technique in substantia gelatinosa neurons an adult rat spinal cord slice with attached dorsal root.Norepinephrine inhibited amplitude monosynaptically evoked A delta-fiber and C-fiber excitatory postsynaptic currents a reversible...

The deacetylation and gelation of konjac glucomannan (KGM) following alkali addition was investigated by Fourier transform infrared, while the rheological properties KGM with different molecular weights were studied dynamic viscoelastic measurements in shear mode penetration force tests. It found that occurred after significant had taken place. Rheometrical studies revealed exhibited characteristics small amplitude oscillatory flow. For samples fractionated lower weights, a decrease both...

To elucidate the mechanisms of antinociception mediated by descending noradrenergic pathway in spinal cord, effects noradrenaline (NA) on noxious synaptic responses substantia gelatinosa (SG) neurones, and postsynaptic actions NA were investigated rats using an vivo whole-cell patch-clamp technique. Under urethane anaesthesia, rat was fixed a stereotaxic apparatus after lumbar cord exposed. In current-clamp mode, pinch stimuli applied to ipsilateral hindlimb elicited barrage EPSPs, some...

Transcutaneous sine-wave stimuli at frequencies of 2000, 250 and 5 Hz (Neurometer) are thought to selectively activate Aβ, Aδ C afferent fibers, respectively. However, there few reports test the selectivity these cellular level. In present study, we analyzed action potentials (APs) generated by applied dorsal root in acutely isolated rat ganglion (DRG) preparations using intracellular recordings. We also measured excitatory synaptic responses evoked transcutaneous substantia gelatinosa (SG)...

Background The activation of descending norepinephrine-containing fibers from the brain stem inhibits nociceptive transmission at spinal level. How these noradrenergic pathways exert analgesic effect is not understood fully. Membrane hyperpolarization substantia gelatinosa (Rexed lamina II) neurons by alpha2 receptors may account for depression pain transmission. In addition, it possible that norepinephrine affects transmitter release in gelatinosa. Methods Adult male Sprague-Dawley rats...

The substantia gelatinosa (SG) of the spinal dorsal horn shows significant morphological heterogeneity and receives primary afferent input predominantly from A delta- C-fibres. Despite numerous anatomical physiological studies, correlation between morphology functional connectivity, particularly in terms inhibitory inputs, remains elusive. To compare excitatory synaptic inputs on individual SG neurones with morphology, we performed whole-cell recordings Neurobiotin-filled-pipettes horizontal...

Stimulation of the rostral ventromedial medulla (RVM) is believed to exert analgesic effects through activation serotonergic system descending spinal dorsal horn; however, how nociceptive transmission modulated by has not been fully clarified. To investigate inhibitory mechanisms affected RVM, an in vivo patch-clamp technique was used record IPSCs from substantia gelatinosa (SG) cord evoked chemical (glutamate injection) and electrical stimulation (ES) RVM adult rats. In voltage-clamp mode,...

1. The membrane properties of substantia gelatinosa (SG) neurons in an vitro adult rat transverse spinal cord slice preparation with attached dorsal root have been examined. Intracellular recordings were obtained from identified SG neurons. 2. Seventy-six percent exhibited a time-dependent anomalous rectification (AR) when the was hyperpolarized resting potential. AR blocked by cesium (Cs+, 2 mM) but not barium (Ba2+, mM). Application Cs+ itself caused hyperpolarization those that expressed...

Abstract The TRPA1 channel has been proposed to be a molecular transducer of cold and inflammatory nociceptive signals. It is expressed on subset small primary afferent neurons both in the peripheral terminals, where it serves as sensor, central nerve endings dorsal horn. substantia gelatinosa (SG) spinal cord key site for integration noxious inputs. SG are morphologically functionally heterogeneous precise synaptic circuits poorly understood. We examined how activation channels affects...

Chronic treatment with calcitonin in osteoporotic patients alleviates the pain associated this condition by an unknown mechanism. In ovariectomized rats that develop osteoporosis and hyperalgesia, we examined whether a functional change serotonergic systems spinal dorsal horn was involved, using whole-cell recordings from substantia gelatinosa neurons cord slices [(3)H]8-hydroxy-2(di-n-propylamino)tetralin ([(3)H]8-OH-DPAT) binding. Hyperalgesia could be attributed to elimination of...

1. Synaptic responses of 46 substantia gelatinosa (SG) neurones in the spinal dorsal horn to cutaneous mechanical and/or thermal stimuli were investigated an vivo rat preparation with whole-cell patch-clamp recordings. The clamped identified as being SG based on either their morphological features by intrasomatic injection biocytin or depth from surface cord. 2. In all examined where spontaneous EPSCs occurred, pinch (noxious) and air (innocuous) applied ipsilateral hindlimb elicited a...

Although intrathecal administration of baclofen, a selective GABA(B)-receptor agonist, is known to have an antinociceptive effect on various pain models, the role presynaptic GABA(B) receptors in antinociception not well characterized. In present study, action baclofen primary afferent-evoked glutamatergic excitatory transmission was examined substantia gelatinosa (SG) neurons adult rat spinal cord slice with attached dorsal root, prepared from lumbar segment, by use blind whole-cell...

Blind patch clamp recordings were made from substantia gelatinosa (SG) neurones in the adult rat spinal cord slice to study mechanisms of cholinergic modulation GABAergic inhibition. In majority SG tested, carbachol (10 μM) increased frequency (677 % control) spontaneous inhibitory postsynaptic currents (IPSCs). A portion these events appeared result generation spikes by interneurones, since large amplitude IPSCs eliminated tetrodotoxin (1 μM). The effect on was mimicked neostigmine,...

To know a functional role of inhibitory synaptic responses in transmitting noxious and innoxious information from the periphery to rat spinal dorsal horn, we examined postsynaptic currents (IPSCs) elicited substantia gelatinosa (SG) neurons by mechanical stimuli applied skin using newly developed vivo patch-clamp technique. In majority (80%) SG examined, brush stimulus ipsilateral hind limb produced barrage IPSCs that persisted during stimulus, while pinch evoked only at its beginning end....

Background It has been reported previously that norepinephrine, when applied to the spinal cord dorsal horn, excites a subpopulation of horn neurons, presumably inhibitory interneurons. In current study, authors tested whether norepinephrine could activate interneurons, specifically those are "GABAergic." Methods A transverse slice was obtained from segment lumbar isolated adult male Sprague-Dawley rats. Whole-cell patch-clamp recordings were made substantia gelatinosa neurons using blind...