CORE Metadata, citation and similar papers at core.ac.uk Provided by Elsevier - Publisher Connector Progress in Neuro-Psychopharmacology & Biological Psychiatry 44 (2013) 39–50 Contents lists available at SciVerse ScienceDirect Progress in Neuro-Psychopharmacology & Biological Psychiatry journal homepage: www.elsevier.com/locate/pnp The activation of α1-adrenoceptors is implicated in the antidepressant-like effect of creatine in the tail suspension test Mauricio P. Cunha, Francis L. Pazini, Ágatha Oliveira, Luis E.B. Bettio, Julia M. Rosa, Daniele G. Machado, Ana Lúcia S. Rodrigues ⁎ Department of Biochemistry, Center of Biological Sciences, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, SC, Brazil article info abstract Article history: The antidepressant-like activity of creatine in the tail suspension test (TST) was demonstrated previously by Received 5 September 2012 our group. In this study we investigated the involvement of the noradrenergic system in the Received in revised form 8 January 2013 antidepressant-like effect of creatine in the mouse TST. In the first set of experiments, creatine administered Accepted 18 January 2013 by i.c.v. route (1 μg/site) decreased the immobility time in the TST, suggesting the central effect of this com- Available online 26 January 2013 pound. The anti-immobility effect of peripheral administration of creatine (1 mg/kg, p.o.) was prevented by the pretreatment of mice with α-methyl-p-tyrosine (100 mg/kg, i.p., inhibitor of tyrosine hydroxylase), Keywords: α α Antidepressant prazosin (1 mg/kg, i.p., 1-adrenoceptor antagonist), but not by yohimbine (1 mg/kg, i.p., 2-adrenoceptor Creatine antagonist). Creatine (0.01 mg/kg, subeffective dose) in combination with subeffective doses of amitriptyline Noradrenaline (1 mg/kg, p.o., tricyclic antidepressant), imipramine (0.1 mg/kg, p.o., tricyclic antidepressant), reboxetine Tail suspension test (2 mg/kg, p.o., selective noradrenaline reuptake inhibitor) or phenylephrine (0.4 μg/site, i.c.v., α1- adrenoceptor agonist) reduced the immobility time in the TST as compared with either drug alone. These results indicate that the antidepressant-like effect of creatine is likely mediated by an activation of α1- adrenoceptor and that creatine produces synergistic effects in the TST with antidepressants that modulate noradrenaline transporter, suggesting that an improvement in the response to the antidepressant therapy may occur when creatine is combined with these antidepressants. Furthermore, the synergistic effect of cre- atine (0.01 mg/kg, p.o.) and reboxetine (2 mg/kg, p.o.) combination was abolished by the α1-adrenoceptor antagonist prazosin, indicating that the antidepressant-like effect of combined therapy is likely mediated by an activation of α1-adrenoceptor. © 2013 Elsevier Inc. Open access under the Elsevier OA license. 1. Introduction Besides the monoaminergic hypothesis, impairment in the brain energetic metabolism has been implicated in the pathophysiology of de- Depression is one of the most common illnesses characterized by a pression. Several studies have demonstrated alterations in high-energy broad range of symptoms, including altered mood and cognitive func- phosphate metabolism in subjects with depression (Kato et al., 1992; tions, loss of interest or pleasure, feelings of guilt or low self-worth, Volz et al., 1998). Indeed, a hypoactive prefrontal cerebral energy metab- disturbed sleep or appetite, low energy and recurrent thoughts of olism has been reported in unipolar and bipolar depression (Forester et death or suicide. The antidepressants used for the treatment of this al., 2009; Ketter et al., 2001). Of note, antidepressants treatment in- disorder act by increasing the availability of monoamines (serotonin, creased the energetic metabolism in the brain, since antidepressants noradrenaline and dopamine) in the synaptic cleft by blocking their treatment increased the citrate synthase activity in the mitochondrial reuptake (tricyclics, selective serotonin reuptake inhibitors, selective brain (Hroudova and Fisar, 2010), creatine kinase activity in the cerebral noradrenaline reuptake inhibitors and dopamine reuptake inhibitors) cortex (Assis et al., 2009; Réus et al., 2012; Santos et al., 2009; Scaini et al., or its metabolism (monoamine oxidase inhibitors) (Vetulani and 2010) and brain levels of creatine-containing compounds (Papakostas, Nalepa, 2000). Requisite brain regions that mediate these events are 2009; Silveri et al., 2003). Furthermore, electroconvulsive shock in- unknown, although Samson et al. (2011) reported that activation in creased the cerebral glucose utilization in the hippocampus, suggesting the prefrontal cortex seems to play a crucial role in the treatment that this intervention that is well-known to cause antidepressant effect, responses of patients with major depression. increases metabolic rates (Orzi et al., 1987). It is, therefore, feasible to suppose that agents that improve cellular bioenergetics may be useful in the treatment of depression. Abbreviations: AMPT, α-methyl-p-tyrosine; ANOVA, analysis of variance; DMSO, In line with this, creatine (N-aminoiminomethyl-N-methylglycine), a dimethylsulfoxide; FST, forced swimming test; TST, tail suspension test. ⁎ Corresponding author. Tel.: +55 48 3721 5043; fax: +55 48 3721 9672. guanidine compound that plays a pivotal role in brain energy homeostasis E-mail addresses: [email protected], [email protected] (A.L.S. Rodrigues). (Andres et al., 2008)andpresentasignificant role in the pathophysiology 0278-5846 © 2013 Elsevier Inc. Open access under the Elsevier OA license. http://dx.doi.org/10.1016/j.pnpbp.2013.01.014 40 M.P. Cunha et al. / Progress in Neuro-Psychopharmacology & Biological Psychiatry 44 (2013) 39–50 and treatment of depression. Thus, an inverse correlation between (Pfizer, Brazil). All drugs were dissolved in saline, except creatine, imipra- Hamilton Depression Rating Scale scores and white matter creatine mine, amitriptyline and reboxetine which were dissolved in distilled levels was shown (Dager et al., 2004). Furthermore, a single prolonged water. All drugs were administered by intraperitoneal (i.p.) route, except stress and forced swimming stress was reported to decrease creatine creatine, imipramine, amitriptyline and reboxetine which were adminis- concentrations in the rat prefrontal cortex (Herring et al., 2008; Kim tered by oral route (p.o.) by gavage and creatine and phenylephrine that et al., 2010; Knox et al., 2010). Noteworthy, creatine supplementation was administered by intracerebroventricular (i.c.v.) route. All drugs, has been proposed as a putative antidepressant in preclinical studies except those administered centrally, were administered in a constant vol- (Allen et al., 2010, 2012; Cunha et al., 2012) and clinical trials (Kondo ume of 10 ml/kg body weight. et al., 2011,2012;Roitman et al., 2007). However, the mechanisms underlying its antidepressant effects are not well established. Our 2.3. I.c.v. administration group recently demonstrated that an acute administration of creatine to mice elicits an antidepressant-like effect in the tail suspension test I.c.v. administration was performed using a microsyringe (25 μl, Ham- (TST) dependent on the dopaminergic activation (Cunha et al., 2012). ilton) connected to a 26-gauge stainless-steel needle that was inserted Furthermore, considering that noradrenaline terminals regulate extra- perpendicularly 2 mm deep through the skull according to the procedure cellular dopamine concentrations in the prefrontal cortex (Yamamoto originally described by Laursen and Belknap (1986),whichwasmodified and Novotney, 1998), we hypothesized that the antidepressant-like from the method of Haley and McCormick (1957).Briefly, the animals effect of creatine also involves noradrenergic system modulation. were anesthetized with ether and then gently restrained by hand for The noradrenergic system is involved in the regulation of many phys- i.c.v. injections. The sterilization of the injection site was carried out iological and psychological processes, including the modulation of mood. using gauze embedded in 70% ethanol. Under light anesthesia (i.e. just α The -adrenergic receptors modulate noradrenaline release (Rump and that necessary for loss of the postural reflex), the needle was inserted uni- Majewski, 1987), as well as dopamine release (Verheij and Cools, 2009) laterally 1 mm to the midline point equidistant from each eye, at an equal and are therefore potential targets for antidepressant drug development. distance between the eyes and the ears and perpendicular to the plane of Of note, a number of antidepressant drugs have been found to increase the skull. A volume of 5 μl of sterile saline containing the drugs was α 1-adrenoceptors function (Holsboer and Barden, 1996), since they are injected directly into the lateral ventricle, at the following coordinates α able to increase the density of 1-adrenoceptors in the hippocampus from bregma taken from the atlas of Franklin and Paxinos (1997): and cerebral cortex of mice and rats (Deupree et al., 2007; Rehavi et anterioposterior (AP)=−0.1 mm; mediolateral (ML)=1 mm; and dor- α fi al., 1980)andthe 1-adrenoceptor agonist af nity in the cerebral soventral (DV)=−3 mm. Mice exhibited normal behavior within 1 min ń cortex (Klimek et al., 1991; Nowak and Przegali ski, 1988). Moreover, after injection. After completion of the experiments, all animals were α the 1-adrenoceptor blockade in the central nervous system induces decapitated