Elijah Carstens

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We report an anatomically defined opioid-responsive site in the rostral agranular insular cortex (RAIC) of the rat and characterize the antinociception produced by morphine acting within this region. Immunohistochemistry for the mu-opioid receptor identified a discretely localized cluster of densely labeled dendrite-like processes in the agranular insular(More)
We provide evidence for an antinociceptive effect of dopamine in the rat cerebral cortex that is mediated through descending nociceptive inhibition of spinal neurons. Injection of the dopamine reuptake inhibitor GBR-12935 in the rostral agranular insular cortex (RAIC), a cortical area that receives a dense dopaminergic projection and is involved in(More)
The method of retrograde axonal transport of horseradish peroxidase (HRP) was used to identify the locations of cells of origin of the spinothalamic tract in the cat. Injections of from 0.2-3.0 microliter of 30% HRP were made unilaterally in various regions of the somatosensory thalamus. Massive injections of the caudal thalamus in several cats showed the(More)
Psychophysical methods were used to investigate pain in human subjects elicited by controlled freezing of the skin using a novel vortex thermode. When cooling stimuli delivered with a small thermode (7 mm diameter) exceeded the normal cold pain threshold into the sub-zero temperature range (-5 to -11 degrees C), all subjects reported an intense, sharp(More)
Intraspinal microstimulation was used to test the excitability of single cutaneous (sural) A- and C-fibers at their central terminals in the cat. Systemic morphine (1.0–2.6 mg/kg) increased the antidromic threshold to 110% (mean value) of control in C-fibers. In some of the C-fibers this effect was reversed by naloxone. A-fibers were not consistently(More)
The bispectral index (BIS) of the electroencephalogram has recently been used to monitor the depth of anaesthesia in humans. The BIS is a dimensionless number that varies between 0 and 100. We hypothesized that the BIS could also be used to monitor depth of isoflurane anaesthesia in goats. Needle electrodes were placed over the frontal region of the scalp(More)
Many chemicals including nicotine, capsaicin and piperine (pungent chemicals in red and black peppers, respectively) evoke oral pain and irritation via largely unknown neural mechanisms. As a first step in defining the central pathway for oral chemical irritation, we have used an immunohistochemical method to map locations of brainstem neurons expressing(More)
Responses of single lumbar dorsal horn units to noxious radiant heating (50° C, 10 s) of glabrous footpad skin were recorded in cats anesthetized with sodium pentobarbital and 70% nitrous oxide. The heat-evoked responses of 37/40 units were reduced during electrical stimulation (100 ms trains, 100 Hz, 3/s, 25–600 μA) in the medullary nucleus raphe magnus(More)
Anatomical and electrophysiological methods were used to investigate the projections and response properties of neurons in the second cervical (C2) spinal segment of the cat giving origin to a previously undescribed projection to the ipsilateral thalamus. The method of retrograde axonal transport of horseradish peroxidase (HRP) was used to identify neurons(More)