Effects of fluoxetine administration on mu-opoid receptor immunostaining in the rat forebrain

Gandarias, Juan M.; Echevarrı́a, Enrique; I, Acebes; Abecia, Luis Carlos; Casis, Óscar; Casis, Luı́s

doi:10.1016/s0006-8993(98)01256-6

Cited by 32 publications

(23 citation statements)

References 17 publications

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“…The up-regulation of MOP-eYFP by induction of c-Myc-5-HT 2A -eCFP is likely to be a selective effect because induction of expression of a human CB1 cannabinoid receptor from the equivalent Flp-In T-REx locus does not result in up-regulation of constitutively expressed MOP-eYFP . Interestingly, an increase of MOP receptor level in several regions of rat brain has been observed after chronic treatment with fluoxetine, a selective serotonin reuptake inhibitor (de Gandarias et al, 1999) that should produce elevated brain levels of 5-HT. Similar studies in animals that use selective 5-HT 2A receptor antagonists might clarify the involvement of this or other related receptors for serotonin in MOP receptor up-regulation in native neural tissue.…”

Section: Discussionmentioning

confidence: 99%

Morphine Desensitization, Internalization, and Down-Regulation of the μ Opioid Receptor Is Facilitated by Serotonin 5-Hydroxytryptamine_2AReceptor Coactivation

López-Giménez

Vilaró²,

Milligan

2008

Mol Pharmacol

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Analysis of the distribution of mRNA encoding the serotonin (5-hydroxytryptamine) 5-HT 2A receptor and the opioid peptide receptor in rat brain demonstrated their coexpression in neurons in several distinct regions. These regions included the periaqueductal gray, an area that plays an important role in morphine-induced analgesia but also in the development of tolerance to morphine. To explore potential cross-regulation between these G protein-coupled receptors, the human opioid peptide receptor was expressed stably and constitutively in Flp-In T-REx human embryonic kidney 293 cells that harbored the human 5-HT 2A receptor at the inducible Flp-In locus. In the absence of the 5-HT 2A receptor, pretreatment with the enkephalin agonist [D-Ala 2 ,N-Me-Phe 4 ,Gly 5 -ol]-enkephalin but not with the alkaloid agonist morphine produced desensitization, internalization, and down-regulation of the opioid peptide receptor. Induction of 5-HT 2A receptor expression in these cells resulted in up-regulation of opioid peptide receptor levels that was blocked by both a 5-HT 2A receptor inverse agonist and selective inhibition of signaling via G␣ q /G␣ 11 G proteins. After induction of the 5-HT 2A receptor, coaddition of 5-HT with morphine now also resulted in desensitization, receptor internalization, and down-regulation of the opioid peptide receptor. It has been argued that enhancement of opioid peptide receptor internalization in response to morphine would limit the development of tolerance without limiting analgesia. These data suggest that selective activation of the 5-HT 2A receptor in concert with treatment with morphine might achieve this aim.

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Section: Discussionmentioning

confidence: 99%

Morphine Desensitization, Internalization, and Down-Regulation of the μ Opioid Receptor Is Facilitated by Serotonin 5-Hydroxytryptamine_2AReceptor Coactivation

López-Giménez

Vilaró²,

Milligan

2008

Mol Pharmacol

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“…The treated groups were given daily intraperitoneal injections of fluoxetine chloride according to body weight as described elsewhere (Gandarias et al, 1999;Nowakowska et al, 1997;Vega Matuszcyk et al;Frank et al, 2000). During the same period of time, the control group was given sterilized deionized water, used as the diluent of fluoxetine chloride solution.…”

Section: Methodsmentioning

confidence: 99%

Neonatal Administration of Fluoxetine Decreased Final Sertoli Cell Number in Wistar Rats

Silva

Amorim

et al. 2008

Int. J. Morphol.

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SUMMARY:The aim of the present study was to test the hypothesis that the application of fluoxetine -a highly selective serotonin reuptake inhibitor (SSRI) -in rats during the suckling period induces changes in testicular development. Groups of newborn male rats were randomly assigned with different doses of fluoxetine 24 hours after birth. Each litter stayed with its respective mother during 21 days. Body weight (BW) was measured daily from the 1st -21 st day to calculate daily doses of fluoxetine. 5 mg (T1), 10 mg (T2) 20 mg (T3) or deionized water, were injected intraperitoneally. On the 21 st day, animals were heparinized, anesthetized and blood was collected by cardiac puncture to determine by radioimmunoassay the follicle stimulating hormone (FSH) levels. Testis were removed, weighed, and processed for morphometric analysis. Fluoxetine groups presented decreased body and testicular weight when compared with the control group on the 21 st day. Our findings show that the manipulation of the serotoninergic system with fluoxetine during the critical period of testicular development alters the Sertoli cell population and all testicular parameters related to this cell.

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“…On the other hand, prolonged use of antidepressants may lead to the reduced level of endogenous opioids in the brain [11,[36][37][38] . It was reported that a single dose of imipramine does not affect levels of mRNA responsible for the synthesis of endogenous opioids but prolonged ad- ministration (10 days) led to its increase and changed the concentration of endogenous opioids [39] .…”

Section: Discussionmentioning

confidence: 99%

Modification of Fentanyl Analgesia by Antidepressants

2009

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Clinical practice often requires simultaneous administration of antidepressants with opioids (oncology, rheumatology). Coadministration may either attenuate or potentiate opioid analgesia. The purpose of this paper was to verify how the analgesic action of fentanyl (0.05 mg/kg) is affected by single administration as well as 4- or 21-day premedication with antidepressants characterized by various mechanisms of action. The effects of amitriptyline 3 mg/kg, moclobemide 5 mg/kg, fluoxetine 5 mg/kg and reboxetine 0.08 mg/kg were investigated. Experiments were conducted on normotensive Wistar Kyoto rats. The pain threshold was measured using an analgesimeter. It was concluded that the single administration of an antidepressant increases the analgesic action of fentanyl. Four-day premedication with fluoxetine and reboxetine significantly attenuated the antinociceptive action of fentanyl, whereas 21-day premedication with all antidepressants investigated (fluoxetine, amitriptyline, moclobemide, reboxetine) markedly decreased it. The potential clinical importance of this observation is discussed.

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Effects of fluoxetine administration on mu-opoid receptor immunostaining in the rat forebrain

Cited by 32 publications

References 17 publications

Morphine Desensitization, Internalization, and Down-Regulation of the μ Opioid Receptor Is Facilitated by Serotonin 5-Hydroxytryptamine_2AReceptor Coactivation

Morphine Desensitization, Internalization, and Down-Regulation of the μ Opioid Receptor Is Facilitated by Serotonin 5-Hydroxytryptamine_2AReceptor Coactivation

Neonatal Administration of Fluoxetine Decreased Final Sertoli Cell Number in Wistar Rats

Modification of Fentanyl Analgesia by Antidepressants

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Effects of fluoxetine administration on mu-opoid receptor immunostaining in the rat forebrain

Cited by 32 publications

References 17 publications

Morphine Desensitization, Internalization, and Down-Regulation of the μ Opioid Receptor Is Facilitated by Serotonin 5-Hydroxytryptamine2AReceptor Coactivation

Morphine Desensitization, Internalization, and Down-Regulation of the μ Opioid Receptor Is Facilitated by Serotonin 5-Hydroxytryptamine2AReceptor Coactivation

Neonatal Administration of Fluoxetine Decreased Final Sertoli Cell Number in Wistar Rats

Modification of Fentanyl Analgesia by Antidepressants

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Morphine Desensitization, Internalization, and Down-Regulation of the μ Opioid Receptor Is Facilitated by Serotonin 5-Hydroxytryptamine_2AReceptor Coactivation

Morphine Desensitization, Internalization, and Down-Regulation of the μ Opioid Receptor Is Facilitated by Serotonin 5-Hydroxytryptamine_2AReceptor Coactivation