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Restrictions on the interpretation of spinal reflex modulation in pain and analgesia research

The use of motor reactions including spinal motor mechanisms, such as tail-flick, hot plate test, and flexion reflexes, in research on pain and analgesia requires some precautions, and results should be interpreted with caution. Nocifensive specificity and analgesic selectivity cannot be established unequivocally by only comparing reflexes evoked by noxious stimuli with monosynaptic reflexes. Rath

First-order nociceptive synapses in rat dorsal horn are blocked by an amino acid antagonist

An antagonist to amino acid evoked excitation, γ-d-glutamylglycine (γ-DGG) inhibits, dose-dependently, nociceptive C-fibre evoked field potentials and neuronal discharges in single nociceptive neurons in rat spinal cord. It is concluded that amino acids are possible transmitter substance(s) in nociceptive afferent C-fibres. These results might be useful for development of centrally acting analgesi

The effects of a distant noxious stimulation on A and C fibre-evoked flexion reflexes and neuronal activity in the dorsal horn of the rat

In the halothane-anaesthetized rat, the responses of 49 neurons in the lumbo-sacral cord and the reflex discharge in the common peroneal nerve following electrical stimulation of the sural nerve were recorded in order to study possible relations between neuronal events and reflex nerve discharges. A distant noxious stimulus (to activate Diffuse Noxious Inhibitory Controls (DNIC) of Le Bars et al.1

Functional and topographical properties of field potentials evoked in rat dorsal horn by cutaneous C‐fibre stimulation.

Extracellular field potentials in the lumbosacral dorsal horn evoked by stimulation of cutaneous C fibres in the sural nerve were explored in the halothane‐anaesthetized rat. C‐fibre‐evoked field potentials were prominent in lamina II and lamina V of the dorsal horn. These potentials had a latency of 80‐130 ms and a duration of more than 200 ms. A peak in the C‐fibre‐evoked field potential, termed

Cutaneous inputs to dorsal horn neurones in adult rats treated at birth with capsaicin

Single unit electrical activity has been recorded from dorsal horn neurons in the lumbar spinal cord of adult rats which had been treated at birth with either capsaicin (50 mg kg-1) or with the solvent-vehicle only. The responses of these neurones to electrical stimulation of A- and C-fibres in the sural nerve and to natural stimulation of their cutaneous receptive fields have been studied. In veh

Activity evoked by A- and C-afferent fibers in rat dorsal horn neurons and its relation to a flexion reflex

The responses of 56 neurons recorded in the lumbosacral spinal cord of halothane-anesthetized rats were studied following the application of mechanical stimuli to the skin on the lateral aspect of the paw or electrical stimulation of the sural nerve. Only neurons driven by A- and C-fiber stimulation were considered. The evoked activity in a nerve supplying flexor muscles, the common peroneal nerve

Segmental action of morphine and acupuncture-like stimulation in the dorsal horn of the rat as visualized by the 14C-2-deoxyglucose method

It is not clear where analgesic measures such as morphine and acupuncture have their sites of action. Since analgesia from acupuncturelike stimulation is reversed by naloxone (Sjolund and Eriksson, Brain Res. 173:295, 1979) it is probably mediated via endorphins. The two analgesic procedures mentioned may thus use similar inhibitory mechanisms. We now present data from autoradiographic measurement

Intrathecally applied morphine inhibits nociceptive C fiber input to the primary somatosensory cortex (SI) of the rat

Nociceptive C fiber input to SI in the halothane-nitrous oxide anesthetized rat was assessed by recording cortical field potentials evoked by noxious thermal cutaneous stimulation with CO2-laser pulses. Morphine topically applied onto the lumbar spinal cord produced a dose-dependent inhibition of nociceptive C fiber input from the hind paw to the contralateral SI. The inhibitory effect of morphine

Site of action of antinociceptive acupuncture like nerve stimulation in the spinal rat as visualized by the 14C-2-deoxyglucose method

Aim: It has been claimed that supraspinal structures are necessary forthe depression of nocifensive behaviour elicited by acupuncture or acupuncturelike (AL) stimulation. However, nocifensive reflexes in the spinal catwere inhibited for long periods by a mechanism releasing opieids on AL conditioning stimulation of groups II-III muscle afferents (Sj~lund and Eriksson, Neurosci.Lett. S3:264:1979).

Effect of current pulse duration in recovering quantitative induced polarization models from time-domain full-response and integral chargeability data

The signal level and shape of induced polarization responses are significantly affected by the current pulse duration and waveform. If not accounted for, this data dependency on the current will propagate trough the inversion to results rendering unquantifiable subsurface models. While this problem has been addressed in full-response induced polarization modelling, questions remain as to how to ac

Familial slipped capital femoral epiphysis

In 50 consecutive cases of slipped capital femoral epiphysis (SCFE) from 49 families, the heredity was analyzed by radiographic examination of the first-degree relatives and by interview regarding the second-degree relatives. In four of the 49 families, SCFE was obvious in one or more first-degree relatives; and in another 13 families (14 relatives), radiographic signs of SCFE were found besides t

Compensatory changes of in vivo acetylcholine and noradrenaline release in the hippocampus after partial deafferentation, as monitored by microdialysis

Lesions of the fimbria-fornix pathways are known to induce a partial cholinergic and noradrenergic denervation of the hippocampal formation, which is followed by a slow and protracted collateral sprouting by the spared afferents. Using the intracerebral microdialysis technique, compensatory changes in extracellular levels of acetylcholine (ACh) and noradrenaline (NA) have been monitored over time

Slipped capital femoral epiphysis in southern Sweden. Long-term results after femoral neck osteotomy

Opinions differ concerning the treatment of choice for severe slipped capital femoral epiphysis, probably due to the lack of long-term follow-up evaluations on the different methods of treatment. A series of 33 patients with severe slipped capital femoral epiphysis, treated per primam with wedge osteotomy of the femoral neck, were radiographically and clinically reexamined an average of 28 years (

Regulation of neurotrophin and trkA, trkB and trkC tyrosine kinase receptor messenger RNA expression in kindling

Levels of messenger RNA for nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, and the tyrosine kinase receptors trkA, trkB and trkC have been studied using in situ hybridization in the rat brain 2 h and four weeks after kindling-induced seizures. Epileptiform activity evoked by hippocampal stimulation and exceeding 70 s lead to a concomitant and transient increase of brain- d