Antinociceptive effect of intrathecal morphine in tolerant and nontolerant spinal rats

Siuciak, Judith A.; Advokat, Claire

doi:10.1016/0091-3057(89)90539-x

Cited by 16 publications

(2 citation statements)

References 40 publications

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“…The effects of opioids on spinal cord nociceptive transmission in the presence and absence of spinal cord transections has resulted in conflicting results ( Fields & Basbaum, 1994 ; Le Bars et al ., 1980 ). Interestingly, intrathecal morphine has been reported to be more effective in spinal than in intact rats ( Siuciak & Advokat, 1989 ). In addition, following systemic administration, the morphine concentration in the central nervous system was found to be significantly altered by spinal transection ( Advokat & Gulati, 1991 ).…”

Section: Discussionmentioning

confidence: 99%

Effects of sufentanil and NMDA antagonists on a C‐fibre reflex in the rat

Adam

Gairard

Chauvin

et al. 2001

British J Pharmacology

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1 The eects of intravenous sufentanil and pre-administration of N-methyl-D-aspartate (NMDA) receptor antagonists were tested on a re¯ex triggered by C-®bre activation. The re¯ex was elicited by electrical stimulation of the sural nerve and recorded from the ipsilateral biceps femoris muscle in halothane anaesthetized rats either (1) with an intact neuraxis or (2) in which the brain had previously been transected at the level of the obex. 2 All four doses of sufentanil (0.33, 0.6, 1 and 2 mg kg 71) elicited a depression of the re¯ex in a dose-dependent manner. However, following the expected depression, all doses of sufentanil elicited both facilitation of the re¯ex and tonic inter-stimulus discharges. 3 The C-®bre re¯ex was not modi®ed following intravenous ketamine (1 mg kg 71) or (+)-HA966 (5 or 10 mg kg 71) but, when administered 5 min before sufentanil, these drugs enhanced both the extent and the duration of the depression and strongly reduced the facilitations. 4 In the obex-transected rats, the depressive eect of 1 mg kg 71 sufentanil increased, while the facilitation of the C-®bre re¯ex and the tonic inter-stimulus discharges disappeared. Preadministration of 10 mg kg 71 (+)-HA966 reinforced and prolonged the depressive eect of sufentanil. 5 These results extend previous studies suggesting the involvement of NMDA receptors in the spinal transmission of nociceptive signals. They illustrate the potential of spinal NMDA receptor blockade to both enhance the analgesic, and prevent the pro-nociceptive, eects of sufentanil.

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Section: Discussionmentioning

confidence: 99%

Effects of sufentanil and NMDA antagonists on a C‐fibre reflex in the rat

Adam

Gairard

Chauvin

et al. 2001

British J Pharmacology

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“…Results of numerous studies have shown that the antinociceptive effect of systemic (Advokat & Burton, 1987; Berge & Hole, 1981; Bonnycastle, Cook, & Ipsen, 1953; Irwin, Houde, Bennett, Hendershot, & Seevers, 1951; Wikler, 1950) and spinal (intrathecal; Advokat & Burton, 1987; Siuciak & Advokat, 1989) morphine on the nociceptive tail withdrawal reflex of rats is significantly reduced within 3–4 weeks after spinal transection. Although the mechanisms responsible for this decrease are not known, the evidence indicates that it does not represent a general loss of opiate activity.…”

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confidence: 99%

Comparison of morphine-induced effects on thermal nociception, mechanoreception, and hind limb flexion in chronic spinal rats.

Advokat¹,

Duke²

1999

Experimental and Clinical Psychopharmacology

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The effect of systemic morphine on 3 behaviors in the same group of chronic spinal rats was examined: the tail-flick (TF) reflex to a noxious thermal stimulus, limb withdrawal (LW) to mechanoreceptor (von Frey hair) stimulation, and hind limb flexion (flexor reflex [FR]) elicited by innocuous electrical stimulation of the toes. Compared with intact rats, the potency of morphine on both the TF and the hind paw (but not the forepaw) LW response was significantly reduced. Morphine's effect on the FR depended on the dose. The lowest dose (1.0 mg/kg) produced no change, 4.0 mg/kg decreased response magnitude by approximately 50% (indicating an antispastic effect), and 8.0 mg/kg increased flexor magnitude by 100%. The concurrent TF and FR assays revealed a dissociation of morphine's effects in that the highest dose (8.0 mg/kg) significantly inhibited the nociceptive TF response but facilitated the FR in the same chronic spinal rats. This outcome may be relevant to the phenomenon of "opioid-related myoclonus" recently described in cancer patients, which "was highly associated with nerve dysfunction due to spinal cord lesions" (S. Mercadante, 1998, p. 6).

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Spinal transection reduces both spinal antinociception and CNS concentration of systemically administered morphine in rats

Advokat

Gulati

1991

Brain Research

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Antinociceptive effect of intrathecal morphine in tolerant and nontolerant spinal rats

Cited by 16 publications

References 40 publications

Effects of sufentanil and NMDA antagonists on a C‐fibre reflex in the rat

Effects of sufentanil and NMDA antagonists on a C‐fibre reflex in the rat

Comparison of morphine-induced effects on thermal nociception, mechanoreception, and hind limb flexion in chronic spinal rats.

Spinal transection reduces both spinal antinociception and CNS concentration of systemically administered morphine in rats

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