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Shimizu M, Yoshimura M, Baba K, Ikeda N, Nonaka Y, Maruyama T, Onaka T, Ueta Y. Deschloroclozapine exhibits an exquisite agonistic effect at lower concentration compared to clozapine-N-oxide in hM3Dq expressing chemogenetically modified rats. Front Neurosci 2023; 17:1301515. [PMID: 38099201 PMCID: PMC10720889 DOI: 10.3389/fnins.2023.1301515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/03/2023] [Indexed: 12/17/2023] Open
Abstract
Introduction Within the realm of chemogenetics, a particular form of agonists targeting designer receptors exclusively activated by designer drugs (DREADDs) has emerged. Deschloroclozapine (DCZ), a recently introduced DREADDs agonist, demonstrates remarkable potency in activating targeted neurons at a lower dosage compared to clozapine-N-oxide (CNO). Methods We conducted a comparative analysis of the effects of subcutaneously administered CNO (1 mg/kg) and DCZ (0.1 mg/kg) in our transgenic rats expressing hM3Dq and mCherry exclusively in oxytocin (OXT) neurons. Results and Discussion Notably, DCZ exhibited a swift and robust elevation of serum OXT, surpassing the effects of CNO, with a significant increase in the area under the curve (AUC) up to 3 hours post-administration. Comprehensive assessment of brain neuronal activity, using Fos as an indicator, revealed comparable effects between CNO and DCZ. Additionally, in a neuropathic pain model, both CNO and DCZ increased the mechanical nociceptive and thermal thresholds; however, the DCZ-treated group exhibited a significantly accelerated onset of the effects, aligning harmoniously with the observed alterations in serum OXT concentration following DCZ administration. These findings emphasize the remarkable efficacy of DCZ in rats, suggesting its equivalent or potentially superior performance to CNO at considerably lower dosages, thus positioning it as a promising contender among DREADDs agonists.
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Affiliation(s)
- Makiko Shimizu
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Mitsuhiro Yoshimura
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Kazuhiko Baba
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Naofumi Ikeda
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
- Department of Orthopaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Yuki Nonaka
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Takashi Maruyama
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Tatsushi Onaka
- Division of Brain and Neurophysiology, Department of Physiology, Jichi Medical University, Shimotsuke, Japan
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
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Rowland NE, Fakhar KJ, Robertson KL, Haskell-Luevano C. Effect of serotonergic anorectics on food intake and induction of Fos in brain of mice with disruption of melanocortin 3 and/or 4 receptors. Pharmacol Biochem Behav 2010; 97:107-11. [PMID: 20347864 DOI: 10.1016/j.pbb.2010.03.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 03/05/2010] [Accepted: 03/18/2010] [Indexed: 10/19/2022]
Abstract
Previous studies have indicated that type 3 or 4 melanocortin receptors (MCR) are downstream of the critical anorectic action of drugs that stimulate 5-HT(2C) receptors. To characterize further the receptor types involved, we have studied the effect of serotonergic anorectics in mice with genomic disruption of either MC3R or MC4R, or their combined knockout. In a first experiment, we showed that wild type (WT) and MC4R-/- mice showed comparable inhibition of food intake following acute treatment with dexnorfenfluramine. In a second experiment using WAY-161503, a 5-HT receptor full agonist with selectivity for 2B and 2C subtypes, we found that MC4R-/- responded comparably to WT, while MC3R-/- had reduced sensitivity. Double receptor knockout (DKO) mice responded comparably to WT and MC4R-/-. Surprisingly, brain Fos-ir was not strongly induced in any brain region by WAY-16103 with the exception of the paraventricular nucleus of DKO. These data suggest that MC3Rs may be involved in the response to serotonergic anorectic agents, and more generally in control of food intake.
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Affiliation(s)
- Neil E Rowland
- Department of Psychology, University of Florida, Gainesville, FL, USA.
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Sink KS, Segovia KN, Sink J, Randall PA, Collins LE, Correa M, Markus EJ, Vemuri VK, Makriyannis A, Salamone JD. Potential anxiogenic effects of cannabinoid CB1 receptor antagonists/inverse agonists in rats: comparisons between AM4113, AM251, and the benzodiazepine inverse agonist FG-7142. Eur Neuropsychopharmacol 2010; 20:112-22. [PMID: 20015619 PMCID: PMC2817975 DOI: 10.1016/j.euroneuro.2009.11.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 10/30/2009] [Accepted: 11/10/2009] [Indexed: 01/12/2023]
Abstract
Cannabinoid CB1 inverse agonists suppress food-motivated behaviors, but may also induce psychiatric effects such as depression and anxiety. To evaluate behaviors potentially related to anxiety, the present experiments assessed the CB1 inverse agonist AM251 (2.0-8.0mg/kg), the CB1 antagonist AM4113 (3.0-12.0mg/kg), and the benzodiazepine inverse agonist FG-7142 (10.0-20.0mg/kg), using the open field test and the elevated plus maze. Although all three drugs affected open field behavior, these effects were largely due to actions on locomotion. In the elevated plus maze, FG-7142 and AM251 both produced anxiogenic effects. FG-7142 and AM251 also significantly increased c-Fos activity in the amygdala and nucleus accumbens shell. In contrast, AM4113 failed to affect performance in the plus maze, and did not induce c-Fos immunoreactivity. The weak effects of AM4113 are consistent with biochemical data showing that AM4113 induces little or no intrinsic cellular activity. This research may lead to the development of novel appetite suppressants with reduced anxiogenic effects.
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Affiliation(s)
- K S Sink
- Dept. of Psychology, University of Connecticut, Storrs, CT 06269-1020, USA
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Coşkun S, Gönül B, Ozer C, Erdoğan D, Elmas C. The effects of dexfenfluramine administration on brain serotonin immunoreactivity and lipid peroxidation in mice. Cell Biol Toxicol 2006; 23:75-82. [PMID: 17009098 DOI: 10.1007/s10565-006-0107-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2006] [Accepted: 07/27/2006] [Indexed: 11/30/2022]
Abstract
Obesity continues to be an increasing health problem in worldwide and antiobesity drugs have commonly been used by obese patients. During the use of anorectic drugs, the antioxidant defense may be affected, especially by reactive oxygen species. It was decided to investigate the effects of dexfenfluramine on body weight, daily food intake, brain thiobarbituric acid-reactive substances (TBARS), glutathione (GSH) and nitric oxide (NO) levels, and 5-HT immunoreactivity. Mice were divided into two groups each containing 8 Swiss Albino adult (6 months) mice. Group 1, untreated, was used as a control; group 2 was treated with dexfenfluramine 0.4 mg/kg per day intraperitoneally for 7 days. Brain TBARS and GSH levels were assayed spectrophotometrically. The stable end-products of NO, nitrite and nitrate, were analyzed spectrophotometrically. Brain tissue 5-HT immunoreactivity was observed using an immunohistochemical method. There were significant decreases in body weight in the dexfenfluramine group (p < 0.05). Although brain GSH and NO(x) levels decreased significantly, brain TBARS levels increased in the dexfenfluramine group (p < 0.05). Brain 5-HT immunoreactivity also increased in the dexfenfluramine-treated group compared to control. In conclusion, our findings show that dexfenfluramine is effective in achieving weight loss and also increases lipid peroxidation in mouse brain.
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Affiliation(s)
- S Coşkun
- Department of Biology, Faculty of Arts and Science, Gazi University, Ankara, Turkey.
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Ozer C, Gönül B, Elmas C, Erdoüan D, Ercan ZS. Effects of dexfenfluramine on serotonin levels of mice ileum, contractility, glutathione and malondialdehyde level. Mol Cell Biochem 2005; 280:151-7. [PMID: 16311917 DOI: 10.1007/s11010-005-8842-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Accepted: 06/16/2005] [Indexed: 11/30/2022]
Abstract
UNLABELLED Dexfenfluramine is one of the anorectic drugs that suppresses food intake which acts via inhibition of reuptake of serotonin into brain terminal. Gastrointestinal tract is the main source of peripheral serotonin which is involved in the regulation of gastrointestinal motility. During the use of anorectic drugs, the antioxidant defence is affected especially by reactive oxygen species. The purpose of this study to search: The effect of dexfenfluramine on serotonin levels of ileum and the effect of dexfenfluramine on ileal contractility and oxidative stress. MATERIALS AND METHODS Twenty-two adult male Swiss-albino mice were divided two groups (1) Control, (2) Dexfenfluramine treated (i.p. twice a day 0.2 mg kg(-1) in 0.2 ml saline solution for 7 days). Animal body weights were recorded at the beginning and at the end of the experimental period. Ileum tissues contractile responses to different concentrations of KCl and acethycholine were recorded on polygraph. In the meantime ileal tissue malondialdehyde, a product of lipid peroxidation, and glutathione, endogenous antioxidant levels were assessed by spectrophotometric methods. Ileal tissue serotonin level determined by immunohistochemical method. Body weights decrease and ileal contractile response of acethycholine increased significantly by dexfenfluramine treatment. Meanwhile, ileum glutathione levels decreased and malondialdehyde levels increased in dexfenfluramine treated group. Immunohistochemical detection showed that ileal serotonin levels increased by dexfenfluramine treatments. As a conclusion, there is a relationship between increased ileal contractility and oxidant status in dexfenfluramine treated animals. These effects can be related by increased serotonin levels which is induced by dexfenfluramine in ileum.
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Affiliation(s)
- Ciüdem Ozer
- Faculty of Medicine, Department of Physiology, University of Gazi, Ankara, Turkey.
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Fraga IC, Fregoneze JB, Carvalho FLQ, Dantas KB, Azevedo CS, Pinho CB, de Castro E Silva E. Acute fluoxetine administration differentially affects brain C-Fos expression in fasted and refed rats. Neuroscience 2005; 134:327-34. [PMID: 15953686 DOI: 10.1016/j.neuroscience.2005.03.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Revised: 02/22/2005] [Accepted: 03/11/2005] [Indexed: 11/30/2022]
Abstract
In the present study we investigated the effect of acute fluoxetine administration on the expression of c-Fos in the rat brain under two different metabolic conditions: fed and fasting states. Wistar male rats, weighing 220+/-30g, received i.p. injections of saline solution or fluoxetine (10mg/kg), and were killed 2 h later. The brains were removed after transcardiac perfusion with phosphate-buffered saline followed by paraformaldehyde, and were then processed for immunohistochemistry. Fos-like immunoreactivity was quantified by a computerized system. Fasted animals faced an 18-h suppression of food intake, while fed groups were submitted to an initial 14-h period of fast followed by a 4-h period in which food was freely available. Both in fasting and fed states, fluoxetine-treated animals presented a significant increase in c-Fos expression in hypothalamic areas, limbic structures, circumventricular areas, and in mesencephalic and rhomboencephalic regions, as compared with saline-treated controls. The quantitative comparison of data obtained from fasted and fed animals showed that fasted rats treated with fluoxetine presented a higher c-Fos expression in the ventromedial hypothalamus and the paraventricular nuclei compared with the fed group, while in fluoxetine-treated fed rats c-Fos expression was higher in the arcuate nuclei, medial amygdala, locus coeruleus and dorsal raphe nuclei, as compared with fasted, fluoxetine-treated animals. These data indicate that the metabolic condition of the animals significantly modifies fluoxetine-induced brain c-Fos expression, suggesting that visceral and behavioral fluoxetine effects may be influenced by the metabolic state of the individual.
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Affiliation(s)
- I C Fraga
- Department of Physiology, Health Sciences Institute, Federal University of Bahia, 40110-100 Salvador, Bahia, Brazil
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Rowland NE, Rokadia S, Green DJ, Robertson K. Relationship between anorexia and loss of serotonin uptake sites in brain of mice and rats receiving d-norfenfluramine or d-fenfluramine. Pharmacol Biochem Behav 2004; 77:541-6. [PMID: 15006465 DOI: 10.1016/j.pbb.2003.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2003] [Revised: 12/11/2003] [Accepted: 12/11/2003] [Indexed: 10/26/2022]
Abstract
Previously, we have shown that repeated administration of d-fenfluramine (D-F) to rats is associated with development of tolerance to the initial anorexia, but that in mice no such tolerance seems to occur. In the first study, we show that chronic administration of neither d-norfenfluramine (D-NF; the principal metabolite of D-F) nor the serotonin (5-HT) 2C receptor agonist m-chlorophenyl-piperazine (mCPP) is associated with the development of anorectic tolerance tested using a dessert protocol. However, compared with mice receiving these drugs for the first time, both of these chronic treatments were associated with a significant attenuation of Fos immunoreactivity (Fos-ir) in several brain regions, including bed nucleus of the stria terminalis, paraventricular hypothalamus, and central nucleus of amygdala. This attenuation is similar to that described previously in rats. Because loss of efficacy of these agents could be related to loss of 5-HT transporter (5-HTT) sites, their presumptive primary mode of action, in the final study we determined the effect of various, low-dose regimens of D-F and D-NF on 5-HT uptake in frontal cortex of mice and rats. We show in mice that D-F causes a greater loss of 5-HT uptake than D-NF, and that at the lowest dose regimen used uptake was unaffected in rats but was reduced in mice. The data are discussed in terms of the species difference in behavioral tolerance and differences in neurochemical profile of D-F and D-NF.
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Affiliation(s)
- Neil E Rowland
- Department of Psychology, University of Florida, POB 112250, Gainesville, FL 32611-2250, USA.
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Rowland NE, Robertson K, Green DJ. Effect of repeated administration of dexfenfluramine on feeding and brain Fos in mice. Physiol Behav 2003; 78:295-301. [PMID: 12576128 DOI: 10.1016/s0031-9384(02)00980-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The present study examines whether repeated administration of dexfenfluramine (DFEN) to mice is associated with progressive attenuation of its anorectic action and induction of Fos-immunoreactivity (Fos-ir) in some brain regions, both known effects in rats. ICR:Cd-1 mice were adapted to receiving for 30 min daily a sweetened milk gelatin dessert in addition to ad libitum access to chow. Mice were then injected with either DFEN (5-10 mg/kg) or saline vehicle every other day. These doses of DFEN acutely suppressed intake by approximately 50% and this action was sustained for at least eight injections. The anorectic effect of DFEN was no different between drug-naïve and DFEN-pretreated mice under conditions that produce complete tolerance in rats. In addition, unlike in rats, the acute anorectic effect of m-chlorophenylpiperazine (mCPP) was unaffected by prior DFEN treatment. Mice were perfused after the intake test on the final experimental day and their brain processed for Fos-ir. DFEN induced Fos-ir in brain regions analogous to those reported in rats and, also, as in rats, DFEN pretreatments reduced substantially the Fos-ir induced by acute DFEN in regions including central nucleus of amygdala, bed nucleus of stria terminalis, and the paraventricular hypothalamus (magno- and parvocellular divisions; PVN). Thus, while DFEN pretreatments reduce the effects of DFEN in many brain regions in both rats and mice, mice are unlike rats insofar as there is no tolerance to the anorectic action, at least in the nondeprivation protocol used here.
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Affiliation(s)
- Neil E Rowland
- Department of Psychology, University of Florida, PO Box 112250, Gainesville, FL 32611-2250, USA.
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