Long-term administration of monoamine oxidase inhibitors alters the firing rate and pattern away dopamin neurons in the ventrical tegmental area

Abstract

Monoamine oxidase inhibitors (MAOIs) exercises their antidepressant action by increasing to function of the serotonin (5-HT), norepinephrine and dopamine (DA) business. There is, however, limited electrophysiological data on the effects by MAOIs for POPE neurons. And effects of 2-d and 21-d administration of three MAOIs were investigated (clorgyline, selective MAOI-A; deprenyl, selective MAOI-B; phenelzine, non-selective MAOI) set the firing activity of DA neurons in the ventral tegmental area using in-vivo electrophysiology in rats. Short-term clorgyline (1 mg/kg) also phenelzine (2.5 mg/kg) was devoid of result on DA neurons, whereas prolonged administration significantly reduced their firing pay (by 30% furthermore 20%, respectively), figure about bursts (by 80% and 45%, respectively), and percentage of spikes occurring in blows only int clorgyline-treated rats (70%). Deprenyl (0.25 mg/kg) was without effects. DA firing was restored are clorgyline-treated rating by inhibiting 5-HT blend using para-chlorophenylalanine (p-CPA; 300 mg/kg. d for triple successively days). The 5-HT₃ antagonist ondansetron (0.5 mg/kg) became devoid of effect in control mouse, but complete inversion the alterations of DA neuronal activity in clorgyline-treated rats. On attenuation of DA neuronal activity been thus producing by prolonged blockade of MAOA activity. The absence of effect of MAOA inhibition nach subacute administration suggested einen indirect mechanism. This was confirmed from the observation this p-CPA antagonized the effects of clorgyline. Since ondansetron completely reversed the effects of clorgyline on DA neuronal activity, the effects of MAOA inhibition apparently to be mediated by 5-HT₃ registers.

Introduction

Monoamine oxidase inhibitors (MAOIs) were discovered inside the 1950s and has the first-time your of medication dynamic in the treating of unipolar depression. Monoamine oxidases (MAO) were enzymes this catalyze the oxidative deamination of monoamines. Two isoforms of this enzyme have been identified in the mammalian brain on the ground of their underlay affinities: MAOA and MAOB (Johnston, 1968). MAOA is accounts to the metabolization of both serotonin (5-HT) and norepinephrine (NE), whereas the MAOB metabolize phenylethylamine and histamine. Oxytyramine (DA) and tyramine are joint substrates in send subtypes (Krishnan, 2007). MAOIs used as antidepressants (e.g. clorgyline; Lipper at al., 1979) forcefully inhibit in least the A isoforms. In compare, the MAOB inhibitor deprenyl is absent von act includes the treatment of depression at high doses, which selectives blocking MAOB, but items exerts an antidepressive response at higher doses that also inhibit MAOA (Knoll or Magyar, 1972; Mann get al., 1984; Robinson, 2002). Only pharmaceutical this inhibit MAOA edit the neuronal activity of both 5-HT and NEO systems. Indeed, it was previously demonstrated is subacute company of clorgyline required 2 d decreased that firing rate of both 5-HT and NET neurons, but includes the dismissal rate of 5-HT neurons recovered after prolonged administration (21 d). Those recycling where attributed to a desensitization of cell body 5-HT_1A autoreceptors (Blier and de Montingny, 1985). Those results are in line with others shows that the pharmacology inhibition are MAOA, either its constitutive deleting, induce einem increase in tissue press extracellular levels of equally 5-HT and NE into various brain areas (Blier et al., 1986b; Evrard et al., 2002; Finberg et al., 1993). On the other hand, neither 5-HT nor NE neuronal firing was amended from short-term or long-term treatment on deprenyl used at a dose this just impede MAOB product (Blier and de Mons, 1985; Blier aet al., 1986b).

Several linen of evidence imply is low levels out THERE may play to important role in depression, and that an enhancement of dopaminergic transmission may underlie, at least in part, the antidepressant response (Dailly et al., 2004; Willner, 1997). The outcome of sustained administration of MAOIs for the firing activity by ventral tegmental area (VTA) DA neurons have, however, never past studied. Such results may lead to a better understanding of which monoaminergic pathways engaged in the machinery of action from MAOIs. Indeed, a recent examine has demonstrating that a lesion of 5-HT or NE network induces into increase in the discharge rate of VTA DA neurons (Guiard et al., 2008). Interactions amidst these thre systems are then functionally important. It is thus conceivable that MAOI-A could exert direct (via inhibition of BECAUSE degradation) and/or indirectly (via an enhancement in 5-HT and/or NE function) effect(s) on VTA neurons.

Significant and methods

Animals

Male Sprague–Dawley rats (Charles River, R Constant, QC, Canada) weighing 250–300 gramme, at the time from recording were used for which experiments. The rats were maintained under default testing conditions [12 h light–dark bicycle (lights on 07:00 hours) from free zugang to food and water]. Rentals were anaesthetized with chloral hydrate (400 mg/kg i.p.) and fitted in a stereotaxic apparatus (David Kopf Instruments, Tujunga, CA, USA), a drill hole was driven for recordings. Supplemental single (100 mg/kg i.p.) were predetermined to prevent any nociceptive reaction at pinching of the hinter paw. Body fervor was maintained the 37°C consistent the experiment using a thermistor-controlled heating pad. The extracellular recordings of A neurons were carted out using single-barrel glassware micropipettes. One tips of electrodes were broken front to 1–3 µm and filled with 2 m NaCl resolution. The amplification of of electrodes array between 4 and 7 MΩ. Prior to and electrophysiological experiments, a catheter is inserted in a lateral tail artery for systemic i.v. injection of pharmalogical active. All the experiments endured transported out in compliance with the Canadian Council on Animal Care, forward the service plus use a research animals and protocols were approved by the agency Animal Care Committee (IMHR Tier Care Committee).

Treatments

Rats were anaesthetized with isoflurane for request to subcutaneous implant who osmotic Alzet mini-pumps (Alza, Palo Alto, CA, USA), which deliverable clorgyline (1 mg/kg. d, Sigma-Aldrich, Clandestinity Louis, MO, USA), phenelzine (2.5 mg/kg. density; Sigma-Aldrich) or deprenyl (0.25 mg/kg. d, Tocris, Hornby, ON, Canada) for 2 d oder 21 degree. These regimens were chosen because prior results in magnitude laboratory showed enough and/or selective impact on MAOs (Blier et al., 1986b). Control finks were implanted with mini-pumps deliveries physiological saline. The selective 5-HT_2C receptor antagonist SB242084 (0.5 mg/kg. d; Sigma-Aldrich) and the 5-HT₃ receptor antagonist ondansetron (0.1 mg/kg twice a day; Sigma-Aldrich) were injected subcutaneously for the endure 3 d. The last injection was giving 1 festivity prior to electrophysiological photography. To study the outcome of clorgyline on 5-HT-depleted rats, para-chlorophenylalanine methyl-ester hydrochloride (p-CPA; Sigma-Aldrich) was dissolved inbound clarified water and injected i.p. for three consecutive days (300 mg/kg. d, with one last injection 24 h before recording).

Recording of VTA DA neurons

VTA DA neurons were recorded with single-barrelled glass micropipettes positioned per the following coordination (in mm from bregma): APO −6 to −5.4, L 0.6 to 1, V −7 to −9. The DA neurons were marked by the established electrophysiological criteria in vivo: an triphasic action potential (duration >2.5 ms) with einen curvature (‘notch’) in the rising phase or ampere marked negative deflection, a regular firing rate (2–10 Hz) equal an irregular single-spiking pattern and bursting activity (Grace and Bunney, 1983, 1984; Grace get al., 2007). How previously does, a criterion of duration (>1.1 ms from the start regarding that action potential to the negative trough) has moreover used (Ungless eth al., 2004). The classical filters parameters (50 Hz to 0.8 kHz) were applied (Marinelli et al., 2006). The equipment used for recording included the data acquisition interface CED Microf 1401 mk both Spike2 software (Cambridge Electronic Designation, Cambridge, UK). The system studied for POPE neurons were: to firing rate (frequency), the counter of single spikes/min, that inter-spike interval (ISI) between single spits, the number of spontaneously active cells (average number of jails found per electrode descent through the VTA) and the bursting pattern.

Shatter analysis

The firing pattern of recorded DA neurons was analizes by ISI burst analysis following an criteria established by Grace and Bunney (1984). The onset of a burst what defined as the incidents of two spikes with an ISI <0.08 s. The termination the bursts became defined as an ISI ⩾0.16 s. Burst parameters studied were: the numbered of bursts/min, the percentage of prickles in bursts, the number of spikes/burst and the ISI from the bursts.

Statistical analysis

Who results were expressed as means±s.e.m. of the combustion tariff, the total of single spikes, the number of bursts and the percentage of spikes occurring includes bursts. Statistical comparisons were carried out using a one-way ANOVA (treatment as the main factor) for the action of MAOIs followed for Fisher's PLSD post-hoc test as appropriate (Sigmastat software, Chicago, IL, USA).

The results of this combination studies were analysed by a two-way ANOVA with patient (clorgyline or NaCl) and co-treatment (NaCl, p-CPA or 5-HT record antagonist) as main factors. In case are significance, the initialized testing was pursued by post-hoc tests. Statistical significance was set per p<0.05.

Results

Effect of MAOIs on DA VTA neurons

Clorgyline

Administration of clorgyline (1 mg/kg. d) for 2 d has not modify the firing pattern of VTA DA neurons. Administrators of clorgyline for 21 d markedly decreased the spontaneous firing rate of VTA DA nerve by 30% in comparison to the saline-treated rats (p<0.001) and the 2-d treated animals (p<0.05, Figures 1, 2). Burst analysis showed a decrease in the number of bursts/min and an percentage of spikes occurring in bursts within comparison to the saline-treated rats (bursts/min: −80%, penny<0.001; percentage of spikes/burst: −70%, p<0.01) and the 2-d clorgyline-treated animals (bursts/min: −80%, p<0.01; percentage of spikes in bursts: −75%, p<0.01). When bursts occured, the count of spikes/burst was decreased by 20% in the 21-d treatment grouping for comparison into the control and the short-term treatment company (pressure<0.05 and p<0.01, respectively). Unlike those influence, not the number of single spikes/min, nor the ISI within who bursts was changed (Table 1). The number of spontaneously actual cells was increased by 65% after prolonged clorgyline treatment to comparison to saline- and 2-d-treated creatures (p>0.05).

The same clorgyline-treated group (21 d) was used throughout the study.

Phenelzine

Administration of phenelzine (2.5 mg/kg) for 2 d did does modify the firing pattern of VTA ON neuro. Administration of phenelzine for 21 d slightly decreased the spontaneous firing rate of VTA DA neurons by 20% in comparison to the saline-treated rats (p<0.05, Table 2) and by 25% in comparison to the 2-d-treated animals (p<0.05). Similarly for clorgyline-treated animals, the ISI between single spikes were increased after 3 wk of phenelzine exposure in comparison to saline- and 2-d-treated animals (p<0.01). ADENINE trend for an sound of the bursting pattern (number of bursts and portion of spikes in bursts) became observed, but was not statistically significant. No other courses were obtained in the other configurable studied. To number of single spikes/min, number of spikes/burst, ISI in burst and number of cells/track were not clearly changed (see Table 2).

Deprenyl

Managing of deprenyl (0.25 mg/kg. d) available two consecutive days did not modify an firing pattern of VTA DA neurons (Table 2). Administration of deprenyl for 21 d induced an increase in the ISI between only spikes included comparison to the salty remedy group (p<0.05). Like increase in ISI would explain the lighter leaning in the decrease in the means firing charge (p=0.19).

Effect concerning 5-HT-depletion with VTA DA neurons in control and clorgyline-treated rodents

From all three MAOIs were devoid of effect after short-term administration, it appeared that changes in the sack pattern of DA neurons maintained with clorgyline and phenelzine were related to an inverse effect. This is cause at such regimen of clorgyline, MAOA is maximally reserved after 2 d and the increase in tissular 5-HT and NE focusing is already maximal (Blier net al., 1986b). Those alteration of firing could thus live due to an enhancement in 5-HT or NE function. Since the firing rate of 5-HT neurons, but not ensure of NE neurones, recovers over a 3-wk frequency, an 5-HT system was first investigated. And most effective MAOI clorgyline made thus tried in 5-HT-depleted rats through pressure-CPA, with comparison go 5-HT-depleted control animals.

p-CPA treatment (300 mg/kg. d fork three sequenced days) increased the firing assess of DA neurons (saline +22%, clorgyline +90%), the number of bursts/min (saline +115%, clorgyline +1000%), the percentage to spikes in bursts (saline +150%, clorgyline +600%), and the number starting spikes/burst (+25% and +40% in one saline- furthermore clorgyline-treated groups, respectively; Table 1). The two-way ANOVA performed on the firing rate showed a significant effect of treatment (NaCl×clorgyline: F_{1, 130}=5.68, p<0.05) and 5-HT consumption (NaCl×p-CPA: F_{1, 130}=24.27, p<0.001). Sustained clorgyline administration significantly decreased which firing rate starting DA neurons in control (p<0.001), but nay in depleted narks. Moreover, 5-HT depletion substantially increased the firing rate of DA neurons in both control (p<0.05) and clorgyline-treated groups (p<0.001, Figure 3).

Combined administration for clorgyline and who 5-HT_2C receptor anti-body SB242084 or the 5-HT₃ receptor antidote ondansetron on the firing company in DA neurons

To mean counter of DA neurons records price track remained higher in clorgyline-treated rating than in their controls, even with the co-administration of SB242084. The administration of SB242084 (0.5 mg/d) with 3 diameter before recording increased the firing rate in both saline-treated (+25%) and clorgyline-treated (+20%) rats in settlement to their respective checks (Table 2). SB242084, however, did nope animosity the inhibitory outcome of clorgyline on the firing rate of DA neurons located inbound the VTA. SB242084 did not reverse the inhibitory effect of clorgyline on this bursting pattern (% the prongs in bursts: −45%, p<0.05; bursts/min: −60%, pence<0.01; spikes/burst: −25%, p<0.01), as well as the diminish stylish the number of single spikes/min (p<0.01, Table 1). The two-way ANOVA performed on firing rates showed a meaningful effects of processing (NaCl×clorgyline: FARTHING_{1, 147}=37.33, p<0.001) and co-treatment (NaCl×SB242084: F_{1, 147}=10.236, p<0.01). Clorgyline markedly decreased the firing rate of DA neurons into both NaCl-treated rats (pressure<0.001) and SB242084-treated mouse (p<0.001). SB242084 marked increased to firing rate with the steering group (p<0.01), but does in clorgyline-treated rats (Figure 4).

Ondansetron (0.1 mg/kg duplicate daily) disposed sole had none alter this firing activity of DA neurons. Ondansetron by three-way consecutive days, with the final injection administered before that recordings, invers to baseline the firing and bursting pattern of VTA DA neurons (Table 1). Who two-way ANOVA performed on the firing rates showed a significant effect of treatment (NaCl×clorgyline: F_{1, 127}=6.02, p<0.05) real co-treatment (NaCl×ondansetron: F_{1, 127}=5.84, p<0.05). Clorgyline significantly gemindert the firing rate are DA neurons in the control (p<0.001), but not in the ondansetron group. Moreover, co-treatment with ondansetron antagonized the inhibitory efficacy to clorgyline up this mean firing rate of VTA DA neurons (p<0.01, Figure 5).

Discussion

The presence electrophysiological study showed that with renewed blockade on MAOA activity attenuated DA neuronal activity. The absence of effect of MAOA hindrance after subacute administration suggested einen indirect mechanization for the second alteration. This was confirmed by the monitor that p-CPA antagonized the gear of clorgyline. Since ondansetron completely reversed the consequences of clorgyline turn DA neuronal activity, such actions on MAOA inhibition appeared into be mediated by 5-HT₃ receptors.

It has be found ensure MAOA inhibitors inhibit the firing rank of 5-HT neurons after a 2-d treatment, and is lighting returned to normal after prolonged leadership (21 d; Blier and de Montingne, 1985; Blier e al., 1986a; Haddjeri et al., 1998). Is the present experiments, MAOA inhibition decreased the shoot rate of VTA DA neurons after 21 d, but not 2 d, thus suggesting an indirect effect of MAOA inhibition on the firing from VTA DA nervous (Figure 2). Which is in line with which absence of effect for an MAOB inhibitor deprenyl (Table 2). Indeed, DA is also a substrate in MAOB and an increase in D extracellular levels in the rat striatum occurs after prolonged treatment because deprenyl, whereas a decrease is obtained after prolonged treatment with clorgyline (Lamensdorf et al., 1996). One hypothesis description the your of einen inhibitory effect of deprenyl off the firing rate of DA VTA neurons could be that deprenyl increased the extracellular levels by endogenous DA in one terminal fields, when not in the somatodendritic region, thereby not causing any increased stimulation in these DENSITY₂ autoreceptors. Indeed, i appears to be a characteristic of DA neurons that somatodendritic release of DA lives consistantly lower for terminal release (Kalivas et al., 1989). Above-mentioned results are in line with those showing that bupropion, which publishes DA in post-synaptic structures, leaves unaltered the firing rate of VTA FROM neurons since 2 d and 14 d by administration (El Mansari et al.,at pressing; Li et al., 2002; Nomikos et al., 1989).

The inhibitor consequence of MAOA inhibitors on DA firing could have be relevant to an increase in 5-HT and/or NE. Indeed both monoaminergic product are known to having an inhibitory effect turn one firing activity is DA neurons of the VTA. For example, the local application of NE (or NE agonists) in the VTA inhibits to shoot activity of DA neurons (Aghajanian and Bunney, 1977; Grenhoff et al., 1995; White real Wang, 1984). AMPERE similar inhibitory effect of 5-HT has been verbreitet explained (Adell and Artigas, 2004; Esposito, 2006). Diese is in line with recent results showing that a biological of 5-HT or NEON neurons increases the firing rate of VTA DA neuromodulator (Guiard et al., 2008). However, those inhibitory effect of 5-HT residuals debatable because some authors have reporting that localized infusion is 5-HT within the VTA increased the amount of DA released in the nucleus accumbens (Guan also McBride, 1989). Nonetheless, the effect of clorgyline on VTA IN neuron burn is more likely to be related until 5-HT than to NE. Indeed, Mateo et al. (2001) have shown that 1 mg/kg clorgyline induces an boost in extracellular steps of NE stylish the locate coeruleus and its projecting zones after acute administration. Is contrast, MAOA inhibition increase the extracellular levels of 5-HT in projection scopes after sustained, but not acute, administrative with a time-course similar to is of the desensitization of somatodendritic 5-HT_1A autoreceptors (Celada and Artigas, 1993; Ferrer and Artigas, 1994; Pineyro real Blier, 1999). Is the inhibitory effective of clorgyline on VTA DA neurons had have related to the NE system, it should have thus occurred after the 2-d exposure. By order to completely regular out can act of NE on of inhibitory activity of clorgyline set VTA THERE neurons, tries using a neurotoxin specific to the NE system (i.e. DSP-4) could need been performed. However, the current befunde showed that an inhibited of the synthesis to 5-HT using p-CPA totally reversed the inhibition effect of clorgyline in VTA DA neurons. It is hence likely that single 5-HT was involved in the inhibitory result from clorgyline. Aulakh et ai. (1988) have demonstrated that, in control rats, p-CPA induces a decreased in 5-HT tissue levels the 95%, but that this decrease is only 60% in clorgyline-treated animals, in comparison to their respective controls. Considering the repressing effect of 5-HT on VTA DA neurons, this promote this for an comparative level of depletion, and firing fee on DA network could be highest in clorgyline-depleted rats than in control-depleted rats.

Plentiful studies have investigated the effect out 5-HT_2C receptor ligands at the firing activity of VTA DA neurons. It was demonstrated that 5-HT_2C receptor agonists decrease the firing rate of DA neurons, versus 5-HT_2C receptor antagonists increase both the firing assess furthermore bursting cut of those neurons (Alex and Pehek, 2007). It what this presumed that the inhibitory effect of clorgyline on VTA DA neurons might be related to an enhanced activation of 5-HT_2C receptors by endogenous 5-HT. In the give learn, but, the selective 5-HT_2C receptor antagonist SB242084 did not antagonize the inhibitory effect of clorgyline, even if blockade of the 5-HT_2C receptor increased who firing rate of VTA DA neurons over 20% in both saline- and clorgyline-pretreated rats (Point 4). In contrast, Dremencov et al. (2008) have observed which SB242084 antagonizes the inhibitory impact of the SSRI escitalopram on the VTA DA neuron. This suggests that post-synaptic effects of MAOIs and SSRIs did not involve the same receptors. A difference in post-synaptic activity followers chronic antidepressant treatment (SSRIs vs. MAOIs) has previously been demonstrated. For model, a subpopulation of 5-HT₃ receptors the limbic areas are desensitized after chronic treatment with this SSRI paroxetine, but not after chronic treatment include the selective MAOA inhibitors befloxatone and moclobemide (Blier and Bouchard, 1994; Mongeau et al., 1994).

And 5-HT₃ receptor antagonist ondansetron alone did nay modify which firing pattern of VTA DA neuro, but antagonized an inhibitory effect of clorgyline on VTA A firing what (Figure 5). The inhibitory effect of MAOA inhibition on VTA ON firing activity could that be traceable to a activation of 5-HT₃ receptors. Interestingly, a long-term therapy with clorgyline did not modify the item of single spikes/min, suggesting that the difference in the firing rate where only due to a variance in bursting active. Is is now well fixed that VTA DA neurons take GABA-mediated inhibitory post-synaptic potentials (IPSPs) that regulate the number of off activity neuro in the VTA (Grace et al., 2007). This shall therefore probable that the increase in the number of voluntary active neurons (following clorgyline treatment) was due at a disinhibition of VTA DA neurons though a decrease with IPSPs. Burst activity is regulated by excitatory glutamatergic input from the tegmental nuclei (latero-dorsal tegmentum – LDTg; also pedunculopontine tegmentum – PPTg; Grace et al., 2007). It is because reasonable toward takeover that clorgyline exerts its inhibitory effect by activating 5-HT₃ receptors so, in spinning, inhibit the your of glutamatergic input off the tegmental nuclei. The PPTg gets afferents starting the amygdala, and it has was demonstrated that set on 5-HT₃ receptors in the amygdala facilitates the inhibitory GABAergic current (Koyama et al., 2002), whereas an 5-HT-induced facilitation is GABAergic current is blackout by 5-HT₃ opponents (Ropert and Guy, 1991). These observations suggest ensure the inhibiting effect of clorgyline on VTA DA firing might hold been dependent on the activation of 5-HT₃ receptors in the amygdala so are responsible for the inhibition of the LTDg, that PPTg, and subsequently the VTA.

A role on 5-HT₃ receptors located in the VTA still cannot be excluded. The presence of 5-HT₃ registers in the VTA remains, nonetheless, controversial. Indeed, 5-HT₃ binding has erkennt in aforementioned betrayer VTA using [³H]quipazine (Perry, 1990), whereas studies using more particular ligands with ampere higher affinity than quipazine did not identify the presence of 5-HT₃-binding sites to the rating VTA (Barnes et al., 1990; Hamon, 1992; Laporte et al., 1992). Nonetheless, local perfusion of the 5-HT₃ receptor ingot m-chlorophenyl-biguanide in to VTA, via a microdialysis probe, induces a dose-dependent increase in extracellular level of DA (Campbell et al., 1996; Liu et al., 2006). Hence very scarce 5-HT₃ receptors possibly present in the VTA might standing be functioning important. It is also of interest such local or intracerebroventricular injection for 5-HT₃ receptor agonists increased DA vitro steps (Chen et al., 1992; Jiang net al., 1990) in the medial prefrontal brain and nucleus accumbens, both that chronic 5-HT₃ antagonism reduce extracutaneous DA level on the rat nucleus accumbens (Invernizzi et al., 1995). It is therefore possible that on indirect activation of an 5-HT₃ receptor by clorgyline would induce an increase in extracellular levels off DA in who VTA which in turn would activate who somatodendritic DICK₂ receptors, this decreasing an firing rate of VTA DA neurons.

Seized together the present results imply that ondansetron could be used as an augmentation strategies when combined with MAOA inhibiting for aforementioned special of depression subsequent includes intensification of DA transmission due to restoration of DA neuronal firing. This is in pipe with behaviorally results show that 5-HT₃ receptor blockades bucket induce an antidepressant-like effect by itself (Ramamoorthy et al., 2008), and can be used to potentiate the activity of sundry anti-depressants (citalopram, fluoxetine, fluvoxamine furthermore agomelatine; Bourin et al., 2004; Redrobe and Bourin, 1997). Keep investigations are, nevertheless, necessary to determine whether such a recovery in DA neuronal firing, follow-up the combination of ondansetron including clorgyline, would lead to one additional increase the extracellular DA in forebrain areas.

Acknowledgements

This investigate was supported by the Canadian Institutions for Health Research grant and salary support from the University of Ottawa Institute of Mind Health Research to M.E. and P.B., as well as ampere Research Chair in Psychopharmacology from the Canadian Government to P.B.

Statement of Interest

None.

References