Anjaneyulu M, Chopra K: Fluoxetine attenuates thermal hyperalgesia through 5-HT_1/2 receptors in STZ-induced diabetic mice. Eur. J. Pharmacol. 497, 285–292 (2004)

Anjaneyulu M, Chopra K: Possible involvement of cholinergic and opioid receptor mechanisms in fluoxetine mediated antinociception response in streptozotocin-induced diabetic mice. Eur. J. Pharmacol. 538, 80–84 (2006)

Arends RH, Hayashi TG, Luger TJ, Shen DD: Co-treatment with racemic fenfluramine inhibits the development of tolerance to morphine analgesia in rats. J. Pharmacol. Exp. Ther. 286, 585–592 (1998)

Bardin L, Colpaert FC: Role of spinal 5-HT_1A receptors in morphine analgesia and tolerance in rats. Eur. J. Pain 8, 253–261 (2004)

Bardin L, Lavarenne J, Eschalier A: Serotonin receptor subtypes involved in the spinal antinociceptive effect of 5-HT in rats. Pain 86, 11–18 (2000)

Brignola G, Calignano A, Rosa MD: Modulation of morphine antinociception in the mouse by endogenous nitric oxide. Br. J. Pharmacol. 113, 1372–1376 (1994)

Chavooshi B, Saberi M, Tehrani SP, Bakhtiarian A, Ahmadiani A, Haghparast A: Vigabatrin attenuates the development and expression of tolerance to morphine-induced antinociception in mice. Pharmacol. Biochem. Behav. 93, 155–159 (2009)

Cohen SP, Christo PJ, Wang S, Chen L, Stojanovic MP, Shields CH et al: The effect of opioid dose and treatment duration on the perception of a painful standardized clinical stimulus. Reg. Anesth. Pain. Med. 33, 199–206 (2008)

Craft RM, Lee DA: NMDA antagonist modulation of morphine antinociception in female vs. male rats. Pharmacol. Biochem. and Behav. 80, 639–649 (2005)

Davis MP, Walsh D, Lagman R, LeGrand SB: Controversies in pharmacotherapy of pain management. Lancet Oncol. 6, 696–704 (2005)

Fuerstein TJ, Gleichauf O, Landwehmeyer GB: Modulation of cortical acetylcholine release by serotonin; the role of substance P interneurons. Naunyn-Schmiedeberg’s Arch. Pharmacol. 354, 618–626 (1996)

Galeotti N, Ghelardini C, Bartolini A: 5-HT_1A agonists induce central cholinergic antinociception. Pharmacol. Biochem. Behav. 57, 835–841 (1997)

Hoffman VL, Vermeyen KM, Adriaensen HF, Meert TF: Effects of NMDA receptor antagonists on opioidinduced respiratory depression and acute antinociception in rats. Pharmacol. Biochem. Behav. 74, 933–941 (2003)

Holtman JR, Jing X, Wala EP: Sex-related differences in the enhancement of morphine antinociception by NMDA receptor antagonists in rats. Pharmacol. Biochem. Behav. 76, 285–293 (2003)

Hyttel J: Pharmacological characterization of selective serotonin reuptake inhibitors (SSRIs). Int. Clin. Psychopharmacol. 9, 19–26 (1994)

Jeong CY, Choi JI, Yoon MH: Roles of serotonin receptor subtypes for the antinociception of 5-HT in the spinal cord of rats. Eur. J. Pharmacol. 502, 205–211 (2004)

Joharchi K, Jorjani M: The role of nitric oxide in diabetes-induced changes of morphine tolerance in rats. Eur. J. Pharmacol. 570, 66–71 (2007)

Jolas T, Aghajanian GK: Opioids suppress spontaneous and NMDA-induced inhibitory postsynaptic currents in the dorsal raphe nucleus of the rat in vitro. Brain Res. 755, 229–245 (1997)

Jolas T, Nestler EJ, Aghajanian GK: Chronic morphine increases GABA tone on serotonergic neurons of the dorsal raphe nucleus: association with an up-regulation of the cyclic AMP pathway. Neuroscience 95, 433–443 (2000)

Kanaan SA, Saade NE, Haddad JJ, Abdelnoor AM, Atweh SF, Jabbur SJ, Garabedian BS: Endotoxin-induced local inflammation and hyperalgesia in rats, a new model for inflammatory pain. Pharmacology 66, 373–379 (1996)

Kawamata T, Omote K, Toriyabe M, Kawamata M, Namiki A: Intracerebroventricular morphine produces antinociception by evoking gamma-aminobutyric acid release through activation of 5-hydroxytryptamine 3 receptors in the spinal cord. Anesthesiology 96, 1175–1182 (2002)

Kuraishi Y, Harada Y, Aratani S, Satoh M, Takagi J: Separate involvement of the spinal noradrenergic and serotonergic systems in morphine analgesia: the differences in mechanical and thermal analgesic test. Brain Res. 273, 245–252 (1983)

Liu W, Wang CH, Cui Y, Mo LQ, Zhi JL, Sun SN, Wang Y et al: Inhibition of neuronal nitric oxide synthase antagonizes morphine antinociceptive tolerance by decreasing activation of p38 MAPK in the spinal microglia. Neurosci. Lett. 410, 174–177 (2006)

Liu ZY, Zhuang DB, Lunderberg T, Yu LC: Involvement of 5-hydroxytryptamine (1A) receptors in the descending antinociceptive pathway from periaqueductal gray to the spinal dorsal horn in intact rats, rats with nerve injury and rats with inflammation. Neuroscience 112, 399–407 (2002)

Lomas LM, Terner JM, Picker MJ: Sex differences in NMDA antagonist enhancement of morphine antihyperalgesia in a capsaicin model of persistent pain: Comparisons to two models of acute pain. Pharmacol. Biochem. Behav. 89, 127–136 (2008)

Machelska H, Labuz D, Przewlocki R, Przewlocki B: Inhibition of nitric oxide synthase enhances antinociception mediated by Mu, Delta and Kappa opioid receptors in acute and prolonged pain in the rat spinal cord. J. Pharmacol. Exp. Ther. 282, 977–984 (1997)

Nayebi AR, Charkhpour M: Role of 5-HT_1A and 5-HT₂ receptors of dorsal and median raphe nucleus in tolerance to morphine analgesia in rats. Pharmacol. Biochem. Behav. 83, 203–207 (2006)

Nayebi AR, Hassanpour M, Rezazadeh H: Effect of chronic and acute administration of fluoxetine and its additive effect with morphine on the behavioural responses in the formalin test in rats. J. Pharm. Pharmacol. 53, 219–225 (2001)

Obata H, Saito S, Sasaki M, Ishizaki K, Goto F: Anti-allodynic effect of intrathecally administered 5-HT₂ receptor agonists in rats with nerve ligation. Pain 90, 173–179 (2001)

Ozdogan UK, Lahdesmaki J, Scheinin M: Influence of prazosin and clonidine on morphine analgesia, tolerance and withdrawal in mice. Eur. J. Pharmacol. 460, 127–134 (2003)

Przewlocki R, Machelska H, Przewlocki B: Inhibition of nitric oxide synthase enhances morphine antinociception in rat spinal cord. Life Sci. 53, 1–5 (1993)

Pullar IA, Corney SL, Colvin EM, Lucaites VL, Nelson DL, Wedley S: LY 367265, an inhibitor of the 5-hydroxytryptamine transporter and 5-hydroxytryptamine_2A receptor antagonist: a comparison with the antidepressant, nefazodone. Eur. J. Pharmacol. 407, 39–46 (2000)

Ramabadran K, Bansinath M, Turndorf H, Puig MM: The hyperalgesic effect of naloxone is attenuated in streptozotocin-diabetic mice. Psychopharmacology (Berl.) 97, 169–174 (1989)

Ramirez MJ, Cenarruzabeitia E, Lasheras B, Del Rio J: 5-HT₂ receptors regulation of acetylcholine release induced by dopaminergic stimulation in rat striatal slices. Brain Res. 757, 17–23 (1997)

Riba P, Ben Y, Smith PA, Furst S, Lee NM: Morphine tolerance in spinal cord is due to interaction between mu- and delta-receptors. J. Pharmacol. Exp. Ther. 300, 265–272 (2002)

Sounvoravong S, Nakashima MN, Wada M, Nakashima K: Decrease in serotonin concentration in raphe magnus nucleus and attenuation of morphine analgesia in two mice models of neuropathic pain. Eur. J. Pharmacol. 484, 217–223 (2004)

Sounvoravong S, Nakashima MN, Wada M, Nakashima K: Modification of antiallodynic and antinociceptive effects of morphine by peripheral and central action of fluoxetine in neuropathic mice model. Acta Biol. Hung. 58, 369–379 (2007)

Vahedi H, Merat S, Rashidioon A, Ghoddoosi A, Malekzadeh R: The effect of fluoxetine in patients with pain and constipation-predominant irritable bowel syndrome: a double-blind randomized-controlled study. Aliment. Pharmacol. Ther. 22, 381–385 (2005)

Xu W, Cui X, Han JS: Spinal serotonin IA and IC/2 receptors mediate supraspinal mu opioid-induced analgesia. Neuroreport 5, 2665–2668 (1994)

Zarrindast MR, Dinkub Z, Homayoun H, Bakhtiarian A: Dopamine receptor mechanisms and morphine tolerance in mice. J. Pysychopharmacol. 16, 261–266 (2002)