Research Article |
Corresponding author: Irina L. Nikitina ( irennixleo@gmail.com ) Academic editor: Mikhail Korokin
© 2022 Irina L. Nikitina, Gulnara G. Gaisina.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Nikitina IL, Gaisina GG (2022) Involvement of monoaminergic system in the antidepressant effect of 3-substituted thietane-1,1-dioxide derivative. Research Results in Pharmacology 8(2): 87-94. https://doi.org/10.3897/rrpharmacology.8.81007
|
Introduction: The aim of the study was to assess the involvement of the monoaminergic system in the antidepressant effect of a new 3-substituted thietane-1,1-dioxide derivative (N-199/1) using tests with several pharmacological antagonists and agonists.
Materials and methods: We conducted 3 sets of experiments in white outbred male mice. In Experiment 1, we assessed the antidepressant effect of N-199/1 in the forced swimming test (FST) and tail suspension test (TST) when administered repeatedly for 2 weeks intraperitoneally (i.p.). In Experiment 2, we evaluated the antidepressant effect of N-199/1 in FST and TST when co-administered with 5HT1A- (WAY100635, 0.1 mg/kg), 5HT2A/2C- (ketanserin, 5 mg/kg), 5HT3- (ondansetron, 1 mg/kg) serotonergic and α2-adrenergic (yohimbine, 1 mg/kg) receptors antagonists. In Experiment 3, we assessed the effect of N-199/1 on the hypothermia induced by i.p. injection of α2-adrenergic receptors agonist clonidine (0.3 mg/kg).
Results and discussion: N-199/1 reduced immobility time (IT) and index of depression (ID) in FST, and did not affect IT in TST, either when administered repeatedly in Experiment 1, or acutely in Experiment 2. In Experiment 2, ketanserin enhanced the effect of N-199/1, decreasing ID by 36%, while WAY100635 and yohimbine antagonized it, increasing ID by 27% and IT by 115%, respectively, in comparison with N-199/1. N-199/1 attenuated the effect of ondansetron, increasing IT by 36%. In Experiment, 3 N-199/1 reduced clonidine-induced hypothermia 1 h after the injection of clonidine. N-199/1 exhibited pronounced antidepressant properties in FST, an agonism to 5HT1A-receptors and an antagonism to 5HT2A/2C- and α2-receptors in tests of neuropharmacological interaction, which indicates an atypical mechanism of its antidepressant action.
Conclusion: The antidepressant effect of N-199/1 is due to the stimulation of 5HT1A-receptors and blockade of 5HT2A/2C- and α2-receptors.
animal outbred strain, antidepressants, clonidine, ketanserin, ondansetron, thietane, WAY100635, yohimbine.
Depression is among the most common mental disorders, affecting about 6% of global population annually (
Systematic studies carried out at the Department of Pharmacology with a course of Clinical Pharmacology of Bashkir State Medical University (BSMU, Ufa) have revealed a promising low-toxic compound – 3-ethoxythietane-1,1-dioxide (laboratory code N-199/1) which exhibits a pronounced antidepressant activity (
The experiments were performed on white outbred male mice weighing 18–23 g in accordance with the requirements of The European Convention for the Protection of Vertebrate Animals Used for Experimental and Other Scientific Purposes (ETS No.123, 1986) and The Rules of Good Laboratory Practice of the Eurasian Economic Union in the Field of Drugs (Decision No. 81 of the Council of the Eurasian Economic Commission dated November 3, 2016 ”On Approval of Rules of Good Laboratory Practice of the Eurasian Economic Union in the Sphere of Circulation of Medicines”). The animals were kept in a 12-hour light regime (08:00–20:00) on a balanced diet (GOST R 50258-92, LLC “GROUP-SPETSKOM”, Moscow, Russia). The study was carried out in accordance with the BSMU research plan on the problem of Drug Discovery and Development, and is approved by the Expert Council on biomedical ethics in theoretical disciplines of BSMU (Minutes No. 9, 2013).
3-ethoxythietane-1,1-dioxide (N-199/1) was synthesized at the Department of Pharmaceutical Chemistry with courses of Analytical and Toxicological Chemistry of BSMU (Head of the Department – Elena E. Klen, Professor, Doctor of Pharmaceutical Sciences). N-199/1 (2 mg/kg) was suspended with Tween-80 (Panreac Quimica S.A.U., Spain), diluted in saline and injected intraperitoneally (i.p.) in accordance with the Experimental design at the rate of 0.2 ml/20 g of animal body weight. The reference drugs fluoxetine (Apo-Fluoxetine, capsules 20 mg, Apotex INC, Canada) and amitriptyline (Amitriptyline, solution for intravenous and intramuscular administration 10 mg/ml, Federal State Unitary Enterprise “Moscow Endocrine Plant”, Russia) were diluted in saline with Tween-80 and injected i.p. at a dose of 10 mg/kg similarly to the compound. In tests of neuropharmacological interaction, we used 5HT1A- antagonist WAY100635 (0.1 mg/kg, WAY100635, Toronto Research Chemicals, Canada), 5HT2A/2C-antagonist ketanserin (5 mg/kg, Ketanserin tartrate, Thermo Fisher, Germany), 5HT3-antagonist ondansetron (1 mg/kg, Latran, solution for intravenous and intramuscular administration 2 mg/ml, Federal State Unitary Enterprise SPC “Pharmzashchita” of FMBA of Russia), α2-antagonist yohimbine (1 mg/kg, Yohimbine hydrochloride, Thermo Fisher, Germany) and α2-agonist clonidine (0.3 mg/kg, Clophelin, solution for intravenous administration 0.1 mg/ml, J.S.C. “Organica”, Russia). All the antagonists and the agonists were also diluted in saline with 1–2 drops of Tween-80 and injected i.p. The control group received an equivalent volume of saline with Tween-80.
To assess the antidepressant activity of N-199/1, forced swimming test (FST) according to
The behavior of the animals was recorded on camera (Panasonic V760), and the following parameters were assessed, using the BrainTest software (
The antidepressant effect of N-199/1 was assessed using FST, TST and OFT when administered i.p. repeatedly. The animals (n=47) were divided into 4 groups: Group 1 (control) received saline, i.p.; Group 2 – amitriptyline (10 mg/kg), i.p.; Group 3 – fluoxetine (10 mg/kg), i.p.; and Group 4 – N-199/1 (2 mg/kg), i.p. N-199/1 and reference drugs were administered once a day i.p. for 14 days; on the Day 15, TST, FST and OFT were performed.
The effect of 5HT1A- (WAY100635, 0.1 mg/kg), 5HT2A/2C- (ketanserin, 5 mg/kg), 5HT3- (ondansetron, 1 mg/kg) serotonergic and α2-adrenergic (yohimbine, 1 mg/kg) receptors antagonists on the activity of N-199/1 in FST and TST was studied according to the methods described in
Group 1 – saline (control group);
Group 2 – N-199/1 (2 mg/kg);
Group 3 – WAY100635 (0.1 mg/kg);
Group 4 – N-199/1 (2 mg/kg) + WAY100635 (0.1 mg kg);
Group 5 – ketanserin 5 mg/kg;
Group 6 – ketanserin 5 mg/kg + N-199/1 (2 mg/kg);
Group 7 – ondansetron (1 mg/kg);
Group 8 – ondansetron (1 mg/kg) + N-199/1 (2 mg/kg);
Group 9 – yohimbine 1 mg/kg;
Group 10 – yohimbine 1 mg/kg + N-199/1 (2 mg/kg).
N-199/1 was administered once i.p. 30 min after a single i.p. injection of antagonists of 5HT2A/2C- (ketanserin)/5HT3- (ondansetron)/α2- (yohimbine) receptors or 30 min before the injection of 5HT1A-antagonist (WAY100635). Thirty minutes after the administration of N-199/1 / WAY100635, FST and TST were performed according to the method described in the design of Experiment 1. The design of Experiment 2 is shown in Fig.
N-199/1 was administered once i.p. 30 min before a single i.p. injection of clonidine, and the severity of the developed hypothermia was assessed every 30 min over 2 h (Fig.
The statistical analysis was performed using the STATISTICA 13.3 software (TIBCO Software Inc., USA). Descriptive statistics (the normality of distribution, median [Me], interquartile range [IQR]) and nonparametrics (Kruskell-Wallis, Mann-Whitney, Friedman, Wilcoxon tests) were calculated (
N-199/1 caused a significant antidepressant effect in FST, reducing IT FST by 62% (p=0.035) and ID by 33% (p<0.001), compared with the control group (Fig.
Effect of N-199/1 on immobility time in the tail suspension test (A), immobility time (B) and index of depression (C) in the forced swimming test, when administered repeatedly (for 2 weeks) intraperitoneally to male mice. Note: graphs show group medians and interquartile range; * – p<0.05 for the Mann-Whitney test compared to the control group.
N-199/1 did not affect IT in TST, which is consistent with the results obtained in single (
In FST, N-199/1 showed antidepressant properties, reducing IT by 49% (p=0.001) and ID by 25% (p<0.001) in comparison with the control group (Fig.
Effect of the combined treatment with N-199/1 and pharmacological antagonists on immobility time (A) and index of depression (B) in the forced swimming test when singly administered intraperitoneally to male mice. Note: graphs show group medians and interquartile range; * – p<0.05 for the Mann-Whitney test compared to the control group; # – p<0.05 for the Mann-Whitney test compared to N-199/1; $ – p<0.05 for the Mann-Whitney test compared to the corresponding antagonist.
All the antagonists significantly decreased ID FST: ondansetron – by 45%, yohimbine – by 33%, WAY100635 – by 11%, and ketanserin – by 27% (p<0.05) compared to the control group (Fig.
WAY100635 (5HT1A-antagonist) reversed the antidepressant effect of N-199/1: the effect of the combination of N-199/1 and the antagonist on the ID was comparable to the effect of the control group (p=0.284), while the ID was 27% (p=0.001) higher than in the only-N-199/1-treated group (Fig.
The combined treatment with ketanserin (5HT2A/2C-antagonist) and N-199/1 caused a more pronounced reduction of ID than in the N-199/1 group (by 36%, p=0.037) or ketanserin group (by 34%, p=0.036), and did not affect IT FST (Fig.
The pre-treatment with ondansetron (5HT3-antagonist) did not change the effect of N-199/1 in the FST: IT and ID in the group “ondansetron + N-199/1” were comparable to the N-199/1 group (p>0.05). At the same time, the ID of the combination was significantly higher than in the ondansetron group (p=0.002, Fig.
The combination of N-199/1 and yohimbine (α2-antagonist) increased IT FST twice compared to the N-199/1 group (p=0.014, Fig.
Clonidine (0.3 mg/kg) reduced the rectal temperature of animals by 1.5–2.4 °C 30–90 min after its administration (p<0.05 for the Mann-Whitney test compared with the control group, p<0.05 for the Wilcoxon test compared with the base level of 0 min) (Fig.
Effect of N-199/1 on clonidine-induced hypothermia. Note: clonidine was administered 30 min after N-199/1 at the time point of 0 min. The graph shows group medians; * – p<0.05 for the Mann-Whitney test compared to the control group, # – p<0.05 for the Mann-Whitney test compared to the clonidine group.
We had previously shown that N-199/1 exhibits significant antidepressant properties after a single i.p. administration to male mice (
It is known that most antidepressants have a delayed onset of action, and their clinical effect develops only in 2–4 weeks (
Similarly to our previous results obtained in a single administration, N-199/1 exhibited pronounced antidepressant properties in FST and did not cause any significant effect in TST, which is characteristic to atypical antidepressants (
The basic tests for studying the mechanism of action of molecules with antidepressant activity are tests of neuropharmacological interaction (
In tests with antagonists, N-199/1 exhibited antidepressant properties in FST, reducing IT and ID, which is consistent with the results obtained when it was administered repeatedly in Experiment 1, or singly in our previous studies (
All the antagonists significantly reduced ID FST, аnd ondansetron (5HT3-antagonist) decreased IT FST as well, causing an antidepressant-like effect in FST in agreement with many in vivo studies. It has been shown that 5HT2A, 5HT2C and 5HT3-antagonists demonstrate antidepressant-like properties in behavioral tests and animal models of depression in rodents (
The agonists of 5HT1A-receptors have shown to produce antidepressant-like effect as well, while the antagonists have no activity in FST (
The combination of the 5HT2A/2C antagonist ketanserin and N-199/1 potentiated the effects of both the antagonist and the molecule on the ID. This suggests that N-199/1 produces its antidepressant effect due to blockade of 5HT2A/2C receptors similar to ketanserin (which is consistent with the data obtained in the reserpine test), or, more likely, via other mechanisms, for example, by stimulating 5HT1A receptors.
The effect of the combination of the 5HT3-antagonist ondansetron and N-199/1 was similar to the effect of N-199/1 itself, so it can be concluded that the compound does not affect 5HT3 receptors. The significant difference between the ondansetron + N-199/1 combination and the ondansetron group by ID is probably related to the serotonin-positive properties of N-199/1.
Yohimbine (α2-antagonist) attenuated the antidepressant effect of N-199/1 on IT FST. An additional test with the α2-agonist clonidine (Experiment 3) allowed us to conclude that the observed findings are due to the blockade of α2-adrenergic receptors, which is consistent with the results of the test of neuropharmacological interaction with reserpine.
N-199/1 exhibits a pronounced antidepressant activity when administered i.p. to male mice singly or repeatedly. The mechanism of action of N-199/1 is probably associated with the stimulation of serotonergic 5HT1A-receptors, blockade of 5HT2A/2C-receptors and α2-adrenergic receptors, since the 5HT1A-antagonist WAY100635 and the α2-antagonist yohimbine counteracted the antidepressant effect of N-199/1 in FST, the 5HT2A/2C-antagonist ketanserin enhanced it, and N-199/1 reversed the hypothermic effect of the α2 agonist clonidine.
The authors declare no conflict of interests.
Irina L. Nikitina, M.D., PhD, Professor of Department of Pharmacology with a course of Clinical Pharmacology, Bashkir State Medical University; head of Llaboratory of Neuropharmacology, Bashkir State Medical University. e-mail: irennixleo@gmail.com, ORCID ID https://orcid.org/0000-0002-6283-5762. The author developed the idea, concept and design of the study, supervised the planning and conducting of research activities, analyzed the results and edited the final version of the article.
Gulnara G. Gaisina, post-graduate student, Assistant of Department of Pharmacology with a course of Clinical Pharmacology, Bashkir State Medical University. e-mail: gugaisy@gmail.com, ORCID ID https://orcid.org/0000-0002-1936-3720. The author took part in experimental work, performed statistical analysis and prepared the final version of the article.