Pro- and anticonvulsant actions of morphine and the endogenous opioids: Involvement and interactions of multiple opiate and non-opiate systems

Frenk, Hanan

doi:10.1016/0165-0173(83)90039-5

Cited by 269 publications

(94 citation statements)

References 83 publications

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“…Inhibition of GABA receptors has been found to potentiate the severity of seizures in animal models [13,14]. In addition, GABA receptor inhibition induced by tramadol can be secondary to its opioid receptor agonist activity [13], and continuing this agonist activity on opioid receptor has been proven to precipitate seizure due to inhibition of GABA pathways [15,16]. In addition to overdose, seizures have been reported in patients receiving tramadol at recommended doses [17].…”

Section: Introductionmentioning

confidence: 99%

Factors Related to Seizure in Tramadol Poisoning and Its Blood Concentration

et al. 2011

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Section: Introductionmentioning

confidence: 99%

Factors Related to Seizure in Tramadol Poisoning and Its Blood Concentration

et al. 2011

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“…Morphine exerts biphasic and dose-dependent anticonvulsant and proconvulsant effects in the experimental model of clonic seizure induced by γ -aminobutyric acid (GABA) transmission blocker penthylenetetrazole (PTZ) (9,10). At the very high doses, morphine induces seizure by itself (11)(12)(13). Animal studies have shown that males and females have different sensitivities to the effects of opioids.…”

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confidence: 99%

Sex and Estrus Cycle Differences in the Modulatory Effects of Morphine on Seizure Susceptibility in Mice

et al. 2004

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Summary:Purpose: To evaluate the effects of sex and estrus cycle on biphasic anticonvulsant and proconvulsant modulation of seizure threshold by morphine.Methods: The threshold for the clonic seizures (CST) induced by acute intravenous administration of γ -aminobutyric acid (GABA)-antagonist pentylenetetrazole (PTZ) was assessed in male and female mice. Estrus cycle was assessed by vaginal smears. The effect of removing circulating sex hormones was assessed by gonadectomy.Results: At baseline, diestrus females had a higher CST compared with males and estrus females. Morphine at lower doses (0.5-3 mg/kg) had a significant anticonvulsant effect in males and estrus females compared with that in vehicle-treated controls, whereas female mice in diestrus phase showed a relative subsensitivity to this effect. Morphine at higher doses (30 and 60 mg/kg) significantly decreased CST in males and diestrus females, with less relative effect in estrus mice. In both phases, morphine exerted stronger effects in males compared with females. Ovariectomy brought the baseline CST to the male level and resulted in significant expression of both phases of morphine effect but did not abolish the sex difference in responsiveness to morphine.Conclusions: The biphasic modulation of seizure threshold is subject to both constitutive sex differences in sensitivity to morphine and hormonal fluctuations during the estrus cycle.

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“…Opioids exert both pro-and anticonvulsant effects depending on the seizure model, animal species, route of drug administration and, most importantly, on the type of the opioid receptor involved [2,14,15]. In this respect a new generation of K opioid receptor agonists deserves attention, since these compounds show consistent anticonvulsive properties in several models of generalized tonic-clonic and limbic seizures [ 12,17 ,20].…”

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Kappa opioid receptor agonists suppress absence seizures in WAG/Rij rats

Przewłocka

Lasoń

Machelska

et al. 1995

Neuroscience Letters

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Involvement of the K: opioid receptor in the regulation of epileptic activity was studied in WAG/Rij rats, a genetic model of absence epilepsy. I.e. v. administration of the K: agonists U50,488H { trans-3,thiophene-4-acetamide), 50 and 150 f1.g/5f1.l each, dose-dependently decreased the number and mean duration of spike wave discharges (SWD). Peripheral administration of U50,488H (10 and 30 mglkg s.c.) also attenuated the seizure activity in this model. The specific K: opioid receptor antagonist nor-binaltorphimine (Nor-BNI, 10 flg/Sfll i.c.v., 18 h before EEG registration) moderately increased the number of SWD, which suggests that endogenous opioids acting through K: receptors may tonically inhibit the seizure activity in these rats. In addition, the enhancement of an absence-like seizure activity induced by the specific ll opioid receptor agonist o-Aia 2 -N-methyi-Phe 4 -Giy 5 -ol-enkephalin (DAMGO, 0.7/.lg/5/.ll i.c.v.) was also attenuated in rats pretreated with U50,488H, U69,593 or PD117,302. These data indicate that activation of the K: opioid receptor exerts an inhibitory effect on absence-like seizure activity in WAG/Rij rats.

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Pro- and anticonvulsant actions of morphine and the endogenous opioids: Involvement and interactions of multiple opiate and non-opiate systems

Cited by 269 publications

References 83 publications

Factors Related to Seizure in Tramadol Poisoning and Its Blood Concentration

Factors Related to Seizure in Tramadol Poisoning and Its Blood Concentration

Sex and Estrus Cycle Differences in the Modulatory Effects of Morphine on Seizure Susceptibility in Mice

Kappa opioid receptor agonists suppress absence seizures in WAG/Rij rats

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