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A simple, rapid technique for intrathecal injections by lumbar puncture in unanesthetized mice is described. Intrathecal [3H]morphine base was not found in significant quantities in either the midbrain or forebrain. Submicrogram quantities of morphine sulfate induced Straub tail response and tail-flick analgesia. These effects were dose related and(More)
The involvement of NMDA receptors in rats with peripheral inflammation and hyperalgesia was evaluated by administration of the non-competitive NMDA receptor antagonist, MK-801. Inflammation and hyperalgesia was induced by intradermal injection of complete Freund's adjuvant (CFA) or carrageenan into the left hind paw. The latency of paw withdrawal from a(More)
We have physiologically characterized the receptive field properties of lamina I projection neurons with cutaneous input in the lumbar spinal cords of control rats and rats with unilateral adjuvant-induced inflammation of the hindlimb. The majority of cells recorded in rats with inflamed limbs demonstrated properties uncharacteristic of this cell population(More)
We have observed a population of lamina I neurons in the cat that has projections to the parabrachial area (parabrachial and cuneiform nuclei). A subpopulation of these neurons also projects to the contralateral thalamus. The majority of projecting cells responded exclusively to noxious stimuli, a few wide-dynamic-range neurons were also observed.(More)
Mice were tested for antinociceptive activity after intrathecal injection of opioid or noradrenergic agonists by lumbar puncture. Opioid agonists with mu or delta activity and adrenergic agonists with alpha activity demonstrated dose-related, receptor-mediated analgesia in the tail-flick assay, s.c. hypertonic saline assay and the intrathecal substance P(More)
Spinal cord application of the kappa-opioid receptor agonists dynorphin (50 nmol) or (1S,2S)U-50,488H (0.19-1.9 mumol) produced changes in the excitability of some superficial dorsal horn nociceptive neurons. One-third of the cells exhibited expansion of their receptive fields as defined using mechanical stimuli following a spinal kappa agonist (dynorphin(More)
We have examined the spinal analgesic activity of opioid agonists and antagonists in a model of short term, unilateral, carrageenan-induced inflammation/hyperalgesia. Rats received a single s.c. injection of carrageenan (2-6 mg in saline) 3-24 h prior to testing hindpaw withdrawal latencies to noxious thermal stimuli. Dose-response curves for intrathecally(More)
We have examined the physiological and morphological characteristics of spinal dorsal horn lamina I neurons with projections to the midbrain in the cat by combining physiological recording of neurons with the intracellular injection of HRP. Lamina I spinomesencephalic neurons were antidromically activated from the region that included the cuneiform nucleus(More)
A major ascending nociceptive pathway from spinal lamina I to the mesencephalon has previously been reported in the cat, rat and monkey. In the present paper, we have used single and double retrograde labeling techniques to describe this projection system and its collateralization to the thalamus in the rat. Injections of wheat germ agglutinin-horseradish(More)