State dependent and/or direct memory retrieval by morphine in mice

Nishimura, Mika; Shiigi, Yasuyuki; Kaneto, Hiroshi

doi:10.1007/bf02245784

Cited by 57 publications

(36 citation statements)

References 13 publications

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“…Our results also showed that pre-test administration of morphine induced state-dependent retrieval of the memory acquired under pre-training morphine infl uence. The present data support the previous studies and indicate that morphine induced amnesia [1,2,5] and this effect of morphine seems to be linked to state-dependent learning [6][7][8] . The restoration of memory by pretest morphine has been shown to be both time-dependent [37] and dose-dependent [4] .…”

Section: Discussionsupporting

confidence: 82%

Effect of the GABAergic System on Memory Formation and State-Dependent Learning Induced by Morphine in Rats

Zarrindast¹,

Noorbakhshnia²,

Motamedi³

et al. 2006

Pharmacology

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In the present study, the effects of intraperitoneal injections of GABA_A receptor agonist and antagonist on memory formation and morphine state-dependent learning were investigated in rats. Pre-training administration of morphine (1–15 mg/kg) in a step-down passive avoidance task induced state-dependent learning with impaired memory retrieval on the test day. The impairment of memory was restored after the pre-test administration of the same dose of morphine. The pre-test administration of the GABA_A receptor agonist, muscimol (0.01, 0.05 and 0.1 mg/kg), significantly decreased state-dependent retrieval induced by pre-test morphine (5 mg/kg). The state-dependency effect of morphine (1 mg/kg) was significantly potentiated by the pre-test administration of the GABA_A receptor antagonist, bicuculline (0.125, 0.25 and 0.5 mg/kg). Furthermore, the pre-training injection of muscimol (0.01 mg/kg) impaired memory retrieval which was restored by pre-test morphine (1, 3 and 5 mg/kg) administration. However, the pre-training administration of bicuculline did not affect retention by itself. In addition, amnesia induced by pre-training morphine (5 mg/kg) was significantly reversed in rats which had received pre-test injections of muscimol (0.01, 0.05 and 0.1 mg/kg). Pre-test injections of bicuculline (0.125, 0.25 and 0.5 mg/kg) significantly decreased morphine-induced amnesia. It is concluded that the GABA_A receptor mechanisms may be involved in the memory formation and it is postulated that these receptors may play an important role in morphine state-dependent learning.

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Section: Discussionsupporting

confidence: 82%

Effect of the GABAergic System on Memory Formation and State-Dependent Learning Induced by Morphine in Rats

Zarrindast¹,

Noorbakhshnia²,

Motamedi³

et al. 2006

Pharmacology

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“…Pre-test administration of the same dose of morphine restored the retrieval to the control level. These effects of morphine that are named state-dependent learning have been demonstrated previously [3,4,29,30] . Moreover, it has been shown that repeated administration of morphine may induce tolerance to its own response [31] .…”

Section: Discussionmentioning

confidence: 89%

Morphine State-Dependent Learning Sensitization and Interaction with Nitric Oxide

et al. 2006

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In the present study, the effects of nitric oxide (NO) precursor L-arginine and L-NAME, a potent inhibitor of NO synthase (NOS), on the expression of sensitization of morphine were investigated. Pre-training administration of morphine (5 mg/kg) impaired memory retrieval compared to pre-training saline-treated animals. Amnesia due to pre-training morphine (5 mg/kg) was restored by pre-test morphine (5 mg/kg).The retrieval impairment was also inhibited in mice which had received once-daily injections of morphine (20 and 30 mg/kg, s.c.) for 3 days, followed by 5 days of no drug treatment before training (in order to induce morphine sensitization). Administration of L-arginine (60 mg/kg/day – 3 days) or L-NAME (20 mg/kg/day – 3 days) before training did not alter morphine state dependency. During acquisition of sensitization, administration of L-arginine (60 mg/kg) 20 min before morphine (10 mg/kg/day, for 3 days) increased, while injection of L-NAME (20 mg/kg) 20 min before morphine (30 mg/kg/day, for 3 days) decreased morphine state dependency. It is concluded that NO is involved in the morphine-induced sensitization.

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“…However, if morphine is injected both posttraining and pre-test, there is no memory impairment (Rezayof et al 2009). This phenomenon is known as morphine statedependent learning (Nishimura et al 1990).…”

Section: Cfcmentioning

confidence: 99%

Reconsolidation may incorporate state-dependency into previously consolidated memories

et al. 2013

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Some memories enter into a labile state after retrieval, requiring reconsolidation in order to persist. One functional role of memory reconsolidation is the updating of existing memories. There are reports suggesting that reconsolidation can be modulated by a particular endogenous process taking place concomitantly to its natural course, such as water or sleep deprivation. Here, we investigated whether an endogenous process activated during a natural/physiological experience, or a pharmacological intervention, can also contribute to memory content updating. Using the contextual fear conditioning paradigm in rats, we found that the endogenous content of an aversive memory can be updated during its reconsolidation incorporating consequences of natural events such as water deprivation, transforming a previously stored memory into a state-dependent one. This updating seems to be mediated by the activation of angiotensin AT1 receptors in the dorsal hippocampus and local infusion of human angiotensin II (ANGII) was shown to mimic the water deprivation effects on memory reconsolidation. Systemic morphine injection was also able to turn a previously acquired experience into a state-dependent memory, reproducing the very same effects obtained by water deprivation or local angiotensin II infusion, and suggesting that other state-dependent-inducing protocols would also be able to contribute to memory updating. These findings trigger new insights about the influence of ordinary daily life events upon memory in its continuing reconstruction, adding the realm of reconsolidation to the classical view of endogenous modulation of consolidation.

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State dependent and/or direct memory retrieval by morphine in mice

Cited by 57 publications

References 13 publications

Effect of the GABAergic System on Memory Formation and State-Dependent Learning Induced by Morphine in Rats

Effect of the GABAergic System on Memory Formation and State-Dependent Learning Induced by Morphine in Rats

Morphine State-Dependent Learning Sensitization and Interaction with Nitric Oxide

Reconsolidation may incorporate state-dependency into previously consolidated memories

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