Increased novelty-induced motor activity and reduced depression-like behavior in neuropeptide Y (NPY)-Y4 receptor knockout mice

“The elevated plus maze was performed as previously described (Pellow et al., 1985; Lister, 1987).”

“, 1985; Lister, 1987; Rodgers and Dalvi, 1997)and the light/dark box (Bourin and Hascoet, 2003; Crawley and Goodwin, 1980) and depressionlike behavior in the forced swim test (Lucki, 1997; Petit-Demouliere et al., 2005; Porsolt et al., 1977) and tail suspension test (Cryan et al.”

“The tail suspension test was performed as described previously (Mayorga and Lucki, 2001; Steru et al., 1985).”

“In addition, basal and novelty-induced locomotor activity were examined by home-cage activity and in the open field test (Hall, 1934; Prut and Belzung, 2003), respectively.”

“The elevated plus maze was performed as previously described (Pellow et al., 1985; Lister, 1987).”

“, 2002; Lucki, 1997), including selective 5-HT reuptake inhibitors and it is independent of swimming ability or thermoregulation (Cryan and Mombereau, 2004; Cryan et al., 2005).”

“In contrast to the traditional forced swim test, the tail suspension test detects the efficacy of a broad spectrum of antidepressant treatments (Cryan et al., 2002; Lucki, 1997), including selective 5-HT reuptake inhibitors and it is independent of swimming ability or thermoregulation (Cryan and Mombereau, 2004; Cryan…”

“…for changes in anxiety-like behavior in the elevated plus maze (Pellow et al., 1985; Lister, 1987; Rodgers and Dalvi, 1997)and the light/dark box (Bourin and Hascoet, 2003; Crawley and Goodwin, 1980) and depressionlike behavior in the forced swim test (Lucki, 1997; Petit-Demouliere et al., 2005;…”

“…behavior in the elevated plus maze (Pellow et al., 1985; Lister, 1987; Rodgers and Dalvi, 1997)and the light/dark box (Bourin and Hascoet, 2003; Crawley and Goodwin, 1980) and depressionlike behavior in the forced swim test (Lucki, 1997; Petit-Demouliere et al., 2005; Porsolt et al., 1977) and…”

“In addition, basal and novelty-induced locomotor activity were examined by home-cage activity and in the open field test (Hall, 1934; Prut and Belzung, 2003), respectively.”

“In brief, chimeric conditional-KO floxed mice (Y2lox/lox or Y4lox/lox) were crossed with oocyte-specific Cre-recombinase expressing C57BL/6 mice (Schwenk et al., 1995).”

“In contrast to other paradigms, this test is not based on increased exploration as an index of anxiolytic-like effects (Cryan and Holmes, 2005).”

“…our present study we investigated male Y4 KO mice for changes in anxiety-like behavior in the elevated plus maze (Pellow et al., 1985; Lister, 1987; Rodgers and Dalvi, 1997)and the light/dark box (Bourin and Hascoet, 2003; Crawley and Goodwin, 1980) and depressionlike behavior in the forced swim…”

“, 1985; Lister, 1987; Rodgers and Dalvi, 1997)and the light/dark box (Bourin and Hascoet, 2003; Crawley and Goodwin, 1980) and depressionlike behavior in the forced swim test (Lucki, 1997; Petit-Demouliere et al., 2005; Porsolt et al., 1977) and tail suspension test (Cryan et al.”

“Several Gi/o coupled receptors (Y1, Y2, Y4, Y5, y6) (Michel et al., 1998) are mediating actions of these peptides.”

“In contrast to the traditional forced swim test, the tail suspension test detects the efficacy of a broad spectrum of antidepressant treatments (Cryan et al., 2002; Lucki, 1997), including selective 5-HT reuptake inhibitors and it is independent of swimming ability or thermoregulation (Cryan and Mombereau, 2004; Cryan…”

“NPY is thought to act primarily through Y1, Y2 and Y5 receptors to which it binds at affinities of 20–100 pM and exerts its prominent effects on anxiety and stress-coping behavior in rats and mice (Heilig, 2004).”

“These tests have been pharmacologically validated to be sensitive to treatment with antidepressant drugs as well as for phenotypic changes in transgenic mice (Cryan et al., 2002; Cryan and Mombereau, 2004).”

“…Lecci et al., 1990; Olivier et al., 2003; Van der Heyden et al., 1997) and the marble burying test (Borsini et al., 2002; Broekkamp et al., 1986; Nicolas et al., 2006; Njung’e and Handley, 1991; Xu et al., 2004), that are independent or even inversely dependent on motor activity, respectively.”

“…Lecci et al., 1990; Olivier et al., 2003; Van der Heyden et al., 1997) and the marble burying test (Borsini et al., 2002; Broekkamp et al., 1986; Nicolas et al., 2006; Njung’e and Handley, 1991; Xu et al., 2004), that are independent or even inversely dependent on motor activity, respectively.”

“E urope PM C Funders A uthor M anuscripts E urope PM C Funders A uthor M anuscripts Parker and Herzog, 1999).”

“Together with altered sympathetic signaling, increased thyrotropin releasing hormone mRNA levels in the paraventricular nucleus of the hypothalamus could be a cause for changes in thermoregulation in Y2/Y4 KO mice (Ribeiro et al., 2001; Sainsbury et al., 2003, 2006; Silva and Larsen, 1983).”

“Like neuropeptide Y (NPY) and peptide YY (PYY) it belongs to the so-called PP-fold peptide family (Berglund et al., 2003; Larhammar, 1996).”

“. uthor M anuscripts E urope PM C Funders A uthor M anuscripts Whereas high Y4 mRNA concentrations are present in the peripheral tissues, they are considerably lower in the brain (Bard et al., 1995; Lundell et al., 1997).”

“Local injections of NPY agonists (Kask et al., 2002) and site-specific deletion of Y2 receptors in amygdaloid nuclei performed by our group demonstrated an important role of the amygdala in Y1 and Y2 receptor-mediated mechanisms of NPY on emotional behavior (Tasan et al., 2007).”

“Pressure injection of NPY and of Y1 receptor agonists, produced pronounced anxiolytic and antidepressant-like effects, notably in the amygdaloid nuclei (Heilig et al., 1993; Kask et al., 2002; Redrobe et al., 2002), whereas injection of Y2 receptor agonists into the basolateral amygdala was anxiogenic (Sajdyk et al.”

“In contrast, repeated i.p. injection of mouse PP in fatty lizer Shoinogy ob/ob obese mice resulted in an anxiolytic effect (Asakawa et al., 2003).”

“…hyperthermia (Borsini et al., 1989; Lecci et al., 1990; Olivier et al., 2003; Van der Heyden et al., 1997) and the marble burying test (Borsini et al., 2002; Broekkamp et al., 1986; Nicolas et al., 2006; Njung’e and Handley, 1991; Xu et al., 2004), that are independent or even…”

“, 1997) and the marble burying test (Borsini et al., 2002; Broekkamp et al., 1986; Nicolas et al., 2006; Njung’e and Handley, 1991; Xu et al., 2004), that are independent or even inversely dependent on motor activity, respectively.”

“Together with altered sympathetic signaling, increased thyrotropin releasing hormone mRNA levels in the paraventricular nucleus of the hypothalamus could be a cause for changes in thermoregulation in Y2/Y4 KO mice (Ribeiro et al., 2001; Sainsbury et al., 2003, 2006; Silva and Larsen, 1983).”

“Like neuropeptide Y (NPY) and peptide YY (PYY) it belongs to the so-called PP-fold peptide family (Berglund et al., 2003; Larhammar, 1996).”

“Thus, Y4 receptor knockout (KO) mice revealed signs of reduced weight gain, altered expression of gonadotropin-releasing hormone as well as increased male aggressive behavior (Asakawa et al., 2003; Sainsbury et al., 2002b, 2003).”

“…Lecci et al., 1990; Olivier et al., 2003; Van der Heyden et al., 1997) and the marble burying test (Borsini et al., 2002; Broekkamp et al., 1986; Nicolas et al., 2006; Njung’e and Handley, 1991; Xu et al., 2004), that are independent or even inversely dependent on motor activity, respectively.”

“…e.g. in the area postrema or in the lateral hypothalamus upon Y4 receptors) may indirectly result in an activation of the medial amygdala and other nuclei related to integration of emotions, linking induction of satiety with potential changes in anxiety-related behavior (Ebner et al., 2004).”

“…from changes in novelty-induced locomotor activity, we additionally used stress-induced hyperthermia (Borsini et al., 1989; Lecci et al., 1990; Olivier et al., 2003; Van der Heyden et al., 1997) and the marble burying test (Borsini et al., 2002; Broekkamp et al., 1986; Nicolas et al., 2006;…”

“Pressure injection of NPY and of Y1 receptor agonists, produced pronounced anxiolytic and antidepressant-like effects, notably in the amygdaloid nuclei (Heilig et al., 1993; Kask et al., 2002; Redrobe et al., 2002), whereas injection of Y2 receptor agonists into the basolateral amygdala was anxiogenic (Sajdyk et al.”

“Y1 receptors mediate their action including anxiolysis primarily at postsynaptic sites, whereas Y2 receptors are mostly located presynaptically on NPY/GABA neurons or at terminals of glutaminergic axons (Parker and Balasubramaniam, 2008), where they inhibit the release of classical transmitters (Adewale et al., 2005;…”

“After an adaptation period of 90 min basal temperature was obtained with a rectal mouse probe (Van der Heyden et al., 1997).”

“We and others demonstrated that deletion of Y2 receptors results in pronounced anxiolytic and antidepressant-like effects (Carvajal et al., 2006; Redrobe et al., 2003; Tschenett et al., 2003).”

“For differentiating anxiolytic-like behavior from changes in novelty-induced locomotor activity, we additionally used stress-induced hyperthermia (Borsini et al., 1989; Lecci et al., 1990; Olivier et al., 2003; Van der Heyden et al., 1997) and the marble burying test (Borsini et al., 2002;…”

“Assays were performed as described previously (Furtinger et al., 2001).”

“Although the exact relation of the nucleus tractus solitarius with anxiety is not established, it is interesting to note that different anxiogenic drugs can activate c-Fos expression in this brain area (Singewald and Sharp, 2000).”

“There exists also an interplay between the nucleus tractus solitarius containing high concentrations of Y4 receptors with the central nucleus of the amygdala, since it receives a dense GABA-ergic input from this brain area (Saha et al., 2000).”

“On the other hand, in vivo, peripheral PP is able to access PP-binding receptors in the area postrema, which circumvents the blood–brain barrier (Whitcomb et al., 1990), and a central action of PP has been established after local injection (McTigue and Rogers, 1995).”

“Nevertheless affinities of NPY and PYY (kB=1 nM) are still in a physiological/ pharmacological range and affinities of PP-fold peptides to Y4 receptors may be different in brain tissue (DiMaggio et al., 1985).”

“We and others demonstrated that deletion of Y2 receptors results in pronounced anxiolytic and antidepressant-like effects (Carvajal et al., 2006; Redrobe et al., 2003; Tschenett et al., 2003).”

“…and the similar signaling pathways used by Y2 and Y4 receptors it may be possible that Y4 receptors, either activated by NPY or by PP, are located presynaptically on terminals in brain stem or hypothalamic nuclei, resulting in an inhibition of transmitter release (Acuna-Goycolea et al., 2005).”

“, 2002), whereas injection of Y2 receptor agonists into the basolateral amygdala was anxiogenic (Sajdyk et al., 2002).”

“For differentiating anxiolytic-like behavior from changes in novelty-induced locomotor activity, we additionally used stress-induced hyperthermia (Borsini et al., 1989; Lecci et al., 1990; Olivier et al., 2003; Van der Heyden et al., 1997) and the marble burying test (Borsini et al.”

“An earlier study reported no difference regarding anxiety behavior after single injections of mPP into the ventricles (Asakawa et al., 1999).”

“In the rat, Y4 receptors are primarily concentrated in the hypothalamus and in the brain stem (Fetissov et al., 2004; Lundell et al., 1997; Whitcomb et al., 1997).”

“Together with altered sympathetic signaling, increased thyrotropin releasing hormone mRNA levels in the paraventricular nucleus of the hypothalamus could be a cause for changes in thermoregulation in Y2/Y4 KO mice (Ribeiro et al., 2001; Sainsbury et al., 2003, 2006; Silva and Larsen, 1983).”

“…primarily at postsynaptic sites, whereas Y2 receptors are mostly located presynaptically on NPY/GABA neurons or at terminals of glutaminergic axons (Parker and Balasubramaniam, 2008), where they inhibit the release of classical transmitters (Adewale et al., 2005; Chen et al., 1997; Greber et al.,…”

“Studies in cell lines expressing recombinant Y4 receptors indicate that PP may be the primary PP-fold peptide acting on Y4 receptors (Berglund et al., 2001; Gehlert et al., 1996).”

“Recently Painsipp et al. (2008) demonstrated an anxiolytic and anti-depressant-like effect of Y4 receptor deletion in female mice.”

“PP is there about 100 times more potent than NPY or PYY in inhibiting binding of [125I]Leu31Pro34PYY and [125I]PP to Y4 binding sites (Yan et al., 1996; Gehlert et al., 1997).”

“Y1 receptors mediate their action including anxiolysis primarily at postsynaptic sites, whereas Y2 receptors are mostly located presynaptically on NPY/GABA neurons or at terminals of glutaminergic axons (Parker and Balasubramaniam, 2008), where they inhibit the release of classical transmitters (Adewale et al., 2005;…”

“In the rat, Y4 receptors are primarily concentrated in the hypothalamus and in the brain stem (Fetissov et al., 2004; Lundell et al., 1997; Whitcomb et al., 1997).”

“PP is there about 100 times more potent than NPY or PYY in inhibiting binding of [125I]Leu31Pro34PYY and [125I]PP to Y4 binding sites (Yan et al., 1996; Gehlert et al., 1997).”

“. uthor M anuscripts E urope PM C Funders A uthor M anuscripts Whereas high Y4 mRNA concentrations are present in the peripheral tissues, they are considerably lower in the brain (Bard et al., 1995; Lundell et al., 1997).”

“Interestingly, Y4 receptors have been also found in human astrocyte cultures, indicating a possible role of glial cells in Y4 receptor actions (Abounader et al., 1999).”

“Together with altered sympathetic signaling, increased thyrotropin releasing hormone mRNA levels in the paraventricular nucleus of the hypothalamus could be a cause for changes in thermoregulation in Y2/Y4 KO mice (Ribeiro et al., 2001; Sainsbury et al., 2003, 2006; Silva and Larsen, 1983).”

“Radiolabeled PP accumulates presumably at the high abundant Y4 receptors in the area postrema (Dumont et al., 2007).”

“Both, Y2 and Y4 receptors predominantly interact with Gi and Gq resulting in inhibition of cAMP accumulation (Freitag et al., 1995; Voisin et al., 2000; Walker et al., 1997).”

“We and others demonstrated that deletion of Y2 receptors results in pronounced anxiolytic and antidepressant-like effects (Carvajal et al., 2006; Redrobe et al., 2003; Tschenett et al., 2003).”

“Both, Y2 and Y4 receptors predominantly interact with Gi and Gq resulting in inhibition of cAMP accumulation (Freitag et al., 1995; Voisin et al., 2000; Walker et al., 1997).”

“Also Y4 mRNA was observed in these areas of the rat indicating that the receptors may be expressed in local neurons (Whitcomb et al., 1990; Trinh et al., 1996; Parker and Herzog, 1999).”

“Y1 receptors mediate their action including anxiolysis primarily at postsynaptic sites, whereas Y2 receptors are mostly located presynaptically on NPY/GABA neurons or at terminals of glutaminergic axons (Parker and Balasubramaniam, 2008), where they inhibit the release of classical transmitters (Adewale et al., 2005;…”

“Interestingly, lesions of the area postrema, containing high concentrations of Y4 receptors, result in increased NPY expression in the amygdala and reduced anxiety (Miller et al., 2002).”

“Studies in cell lines expressing recombinant Y4 receptors indicate that PP may be the primary PP-fold peptide acting on Y4 receptors (Berglund et al., 2001; Gehlert et al., 1996).”

“…of Y2 and Y4 receptors In situ hybridization and receptor autoradiography revealed high levels of Y2 receptor mRNA and binding sites in various limbic brain areas, notably in the amygdala and the hippocampus, as previously described (Dumont et al., 1998; Gackenheimer et al., 2001; Neuroscience.”

“In spite of its apparently relatively low affinity to Y4 receptors, NPY appears to be the only reasonable candidate as a ligand for central Y4 receptors and NPY can still activate Y4 receptors at nanomolar concentration (Bard et al., 1995; McTigue and Rogers, 1995).”

“This is supported by a recent report suggesting an anxiogenic phenotype in PP over-expressing mice (Ueno et al., 2007).”

“In situ hybridization of Y2 receptor mRNA was done essentially as described previously (Schwarzer et al., 1998).”

“Local injections of NPY agonists (Kask et al., 2002) and site-specific deletion of Y2 receptors in amygdaloid nuclei performed by our group demonstrated an important role of the amygdala in Y1 and Y2 receptor-mediated mechanisms of NPY on emotional behavior (Tasan et al., 2007).”

“Other possible mechanisms of action Rhodola extracts are not excluded, such as a possible effect on neuropeptide Y receptors (Larhammar and Salaneck, 2004) and expression of neuropeptide Y which is known play important role in regulation of energy balance, memory and learning, anxiety and depression (Heilig, 2004; Saj…”

“The amygdala, which is a key brain region coordinating behavioural stress responses (McEwen, 2007), contains high levels of NPY and Y1, Y2, Y4 and Y5 receptors (Parker and Herzog, 1999; Kask et al., 2002; Kopp et al., 2002; Wolak et al., 2003; Tasan et al., 2009).”

“The anxiolytic effect of Y4 receptor deletion is amplified by Y2/Y4 receptor double knockout, suggesting a positive interaction of Y2 and Y4 receptors (Tasan et al., 2009).”

“The major receptor subtypes which NPY acts on are the Y1 and Y2 receptors, which are widely distributed in the central nervous system, while the localization of Y4 and Y5 receptors is restricted to particular regions of the brain [82-85].”

“Y4 receptor deficient mice were shown to have reduced anxiety and depression like behavior (Painsipp et al., 2008), and Y2/Y4 double knockout mice showed further decreased depression levels (Tasan et al., 2009).”

“In addition, Y2/Y4 double KO mice showed augmented reduction in immobility time in the FST, compared to Y2-deficient male mice (Tasan et al., 2009).”

“Recently, a number of transgenic mice have been generated to investigate the expression pattern and function of these receptors (Edelsbrunner et al., 2009a, b; Oberto et al., 2007; Painsipp et al., 2008; Tasan et al., 2009).”

“…that NPY ligands can influence emotional behaviours (via Y1, Y2, Y4, and Y5; Kask et al., 2002; Redrobe et al., 2002; Sørensen et al., 2004; Tasan et al., 2009, 2010; MoralesMedina et al., 2010), motivational feeding behaviour (Berglund et al., 2003), as well as locomotor activity and…”

“The open field test was performed to measure overall motor activity, and was performed as described previously (Hall, 1934; Tschenett et al., 2003; Tasan et al., 2009).”

“Despite the limited distribution of the Y4 receptor in the brain, KO of this receptor is associated with reduced anxiety- and depression-related behaviours (Painsipp et al. 2008b, Tasan et al. 2009).”

“Experiments using Y2 receptors or Y4 receptors knock-out mice revealed that the suppression of these receptors subtypes result in a significant restraint of depression (Carvajal et al., 2006; Painsipp et al., 2008b; Tasan et al., 2009; Tschenett et al., 2003).”

“In the central nervous system, Y4 receptors are expressed in specific brain areas, such as the hypothalamus and brain stem (Tasan et al., 2009).”

“Although behavioral experiments on Y2 receptor knockout mice have reported an anxiolytic phenotype (Tschenett et al., 2003; Tasan et al., 2009, 2010), this appears to result from loss of presynaptic Y2 receptors on fibers originating in the central amygdala.”

“The observations in NPY-/- and PYY-/mice are complemented by distinct alterations of anxietyand depression-related behaviour in Y1, Y2 and Y4 knockout mice (Redrobe et al., 2003; Tschenett et al., 2003; Eva et al., 2006; Karl et al., 2006; Painsipp et al., 2008; Tasan et al., 2009).”

“Decreased marble burying in mutant mice can also be interpreted as a sign of lower anxiety (61) or may result from hyperactivity (38, 62, 63).”

“On the other hand, it has been demonstrated that the NPY Y2 and Y4 receptors, but not the Y5 receptor, play an important role in the regulation of emotional behavior in mice (Edelsbrunner et al., 2009; Tasan et al., 2009; Olesen et al., 2012).”

“Interestingly, Y4 receptors are highly expressed in the NTS and peripheral PP injection results in fast activation of NTS neurons (Tasan et al., 2009).”

“Activation of presynaptic Y2 receptors increases anxiety-like responses (Nakajima et al., 1998; Sajdyk et al., 2002; Bacchi et al., 2006), whilst deletion of Y2 receptors results in reduced anxiety-like behaviour (Redrobe et al., 2003; Tschenett et al., 2003; Tasan et al., 2009; 2010).”

“C-terminally truncated human peptide YY (hPYY3-36) was radiolabeled with Na125I (2200 Ci/mmol; PerkinElmer, Boston, USA), and brain sections were incubated with the radiolabeled peptide as described in detail previously (Tasan et al. 2009).”

“In contrast, Y2 and Y4 receptor knockout mice have shown more resilient phenotypes in these tests [206, 207], and the infusion of Y2 antagonists—as well as Y1 agonists—has been related with antidepressant effects [202].”

“In addition, the circadian locomotor behaviour of male Y2−/− and Y4−/− mice has been reported by Tasan et al. (2009).”

“We also assessed basal locomotor activity in the home cage and in the open field test, and spatial learning and memory in the Morris water maze test, respectively [13, 14].”

“…Y and sulfated neurosteroids are known to regulate the same behavioral activities including response to novelty (von Horsten et al., 1998; Tasan et al., 2009), feeding and satiety (Kalra and Kalra, 2004a,b; Ramos et al., 2005; Beck, 2006; Ueno et al., 2008), and reproductive behavior…”

“The role of Y4 receptors in the control of emotional-affective behaviour (Painsipp et al., 2008b; Tasan et al., 2009) may be related to an appreciable expression of Y4 receptors in amygdala, ventral tegmental area, hippocampus, hypothalamus, locus coeruleus and medullary brainstem (Campbell et al.,…”

“The light/dark box arena consisted of a Plexiglas box divided by a small underpass into two compartments: a larger brightly lit zone (58 cm long, 28 cm wide, 750 lux) and a smaller covered dark zone (15 cm long, 28 cm wide) (Crawley, 1985; Tasan et al., 2009).”

“Moreover, the role of Y4R in depression has also been postulated (Painsipp et al. 2008; Tasan et al. 2009).”

“[78] [59]”

“Thus, PP may be considered as a signalling peptide communicating the internal metabolic state to respective CNS centres that generate an adaptive behavioural response.”

“This and additional contribution of the hY4R to anti-secretory effects [3], as well as its possible participation in colon cancer progression [10], and anxiety- and depression-like behaviors [5] suggest this GPCR as a valuable target in several diagnostic and therapeutic approaches.”

“…Formosanwoodmicewerenot related to long-term inbreeding conditions in the laboratory but might be related to alertness Some animals with genetic mutations, such as neuropeptide Y4 receptor knockout mice, show higher levels of locomotion and less anxiety in the open field test (Tasan et al., 2009).”

“This anxiolytic and anti depressant-like phenotype was enhanced in Y2/Y4 double knockout mice compared wit h single Y2 and Y4 knockout mice [290] (see Table 3 for summary).”