Ichiro Harasawa

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Microinjection of kappa opioid receptor (KOR) agonists into the rostral ventromedial medulla (RVM) attenuates mu-opioid receptor mediated antinociception and stress-induced analgesia, yet is also reported to have an analgesic effect. To determine how KOR agonists produce both antinociceptive and antianalgesic actions within the RVM, the KOR agonist U69593(More)
Modulation of sacral spinal dorsal horn neurons by the ventrolateral PAG was studied by extracellular recording combined with microiontophoretic applications of alpha-adrenergic agonists or antagonists. Bicuculline (BIC, 15 ng) microinjected into the ventrolateral PAG produced a consistent inhibition of the responses of nociceptive dorsal horn neurons.(More)
The rostral ventromedial medulla (RVM) is critical for the modulation of dorsal horn nociceptive transmission. Three classes of RVM neurons (ON, OFF, and NEUTRAL) have been described that have distinct responses to noxious stimuli and mu opioid receptor (MOR) agonists. The present study in barbiturate anesthetized rats investigated the effects of the delta(More)
Chronic opiate exposure produces tolerance and hypersensitivity to mechanical and thermal stimulation that involves increased pain facilitation from the rostral ventromedial medulla (RVM). The aim of the present study was to determine the effect of sustained systemic morphine exposure on RVM neurons. Three cell types in the RVM have been described:(More)
BACKGROUND AND OBJECTIVES Stellate ganglion block can promptly relieve acute herpetic pain (AHP) involving the trigeminal and cervical regions. However, repeated blocks are needed to maintain pain relief in most patients with severe AHP. Because continuous epidural block is easily performed using an indwelling catheter, we compared the effect of high(More)
The rostral ventromedial medulla (RVM) exerts both inhibitory and excitatory controls over nociceptive neurons in the spinal cord and medullary dorsal horn. Selective ablation of mu-opioid receptor (MOR)-expressing neurons in the RVM using saporin conjugated to the MOR agonist dermorphin-saporin (derm-sap) attenuates stress and injury-induced behavioral(More)
Microinjection of kappa opioid receptor (KOR) agonists into the rostral ventromedial medulla (RVM) attenuates mu-opioid receptor mediated antinociception and stress-induced analgesia, yet is also reported to have an analgesic effect. To determine how KOR agonists produce both antinociceptive and anti-analgesic actions within the RVM, the KOR agonist U69593(More)
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