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The formalin test for nociception, which is predominantly used with rats and mice, involves moderate, continuous pain generated by injured tissue. In this way it differs from most traditional tests of nociception which rely upon brief stimuli of threshold intensity. In this article we describe the main features of the formalin test, including the(More)
The method commonly used for catheterization of the lumbar subarachnoid space in the rat implies inserting the catheter through the atlanto-occipital (A-O) membrane and moving the catheter caudally along the spinal cord. The method is associated with a considerable morbidity. A method for direct catheterization of the lumbar subarachnoid space was therefore(More)
We have published several reports on long-term potentiation (LTP) in single spinal wide dynamic range (WDR) neurons (responding to both innocuous and noxious stimuli) in urethane-anaesthetised rats. The protocol presented here, with single unit recordings of dorsal horn neurons before and after a nociceptive conditioning stimulation, may be useful in many(More)
The increasing-temperature hot-plate test has several advantages compared to the conventional hot-plate test, but available equipment has been impractical and restricted with regard to stimulus control. We now describe an apparatus consisting of an aluminum plate that is heated and cooled by Peltier elements in contact with its lower surface. Several plates(More)
The N-methyl-D-aspartic acid (NMDA) receptor antagonist D, L-2-amino-5-phosphonopentanoic acid (AP5) caused a stronger inhibition of wind-up in single wide dynamic range (WDR) neurons after carrageenan inflammation compared with control neurons without inflammation in the receptive field. This indicates that even a short period (2.5 h) of inflammation(More)
It is conceivable that plasticity in pain control systems and chronic pain may be due to mechanisms similar to learning. Long-term potentiation (LTP) in the hippocampus is often studied as a model of learning and memory. It has recently been shown that long-term excitation may be induced in single wide dynamic range (WDR) neurones in the spinal dorsal horn(More)
LTP is often studied as a model of synaptic plasticity. Plasticity in pain control systems may involve mechanisms similar to those involved in learning. We recently reported LTP of both the A beta and C-fibre evoked responses of single dorsal horn neurons after a tetanic stimulation of the sciatic nerve, lasting for at least 6 h. In the present paper we(More)
The tail-skin temperature is an important factor in determining tail-flick latency to noxious radiant heat in rats and mice. A simple, non-invasive method for recording the tail-skin temperature during conventional tail-flick testing is described. The method is conveniently performed during conventional tail-flick testing. It does not require additional(More)
The effect of different formalin concentrations on the nociceptive response in the formalin test was examined in mice. Subcutaneous formalin injection induces 2 distinct periods of high licking activity: an early phase lasting the first 5 min, and a late phase lasting 20-30 min after the injection. Formalin concentrations of 0.02-0.2% induced only the early(More)