Chronic exercise prevents repeated restraint stress-provoked enhancement of immobility in forced swimming test in ovariectomized mice

We investigated the role of angiotensin II type 1 (AT1 receptor) and type 2 (AT2 receptor) and MAS receptors present in the medial amygdaloid nucleus (MeA) in behavioral changes in the forced swimming test (FST) evoked by acute restraint stress in male rats. For this, rats received bilateral microinjection of either the selective AT1 receptor antagonist losartan, the selective AT2 receptor antagonist PD123319, the selective MAS receptor antagonist A-779, or vehicle 10 min before a 60 min restraint session. Then, behavior in the FST was evaluated immediately after the restraint (15 min session) and 24 h later (5 min session). The behavior in the FST of a non-stressed group was also evaluated. We observed that acute restraint stress decreased immobility during both sessions of the FST in animals treated with vehicle in the MeA. The decreased immobility during the first session was inhibited by intra-MeA administration of PD123319, whereas the effect during the second session was not identified in animals treated with A-779 into the MeA. Microinjection of PD123319 into the MeA also affected the pattern of active behaviors (i.e., swimming and climbing) during the second session of the FST. Taken together, these results indicate an involvement of angiotensinergic neurotransmissions within the MeA in behavioral changes in the FST evoked by stress.

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Experimental anxiety-depressive state in rats caused by neonatal exposure to the inhibitor of dipeptidyl peptidase IV, diprotin A: effects of imipramine

ZHurnal «Patologicheskaia fiziologiia i eksperimental`naia terapiia» ◽

10.25557/igpp.2017.4.8517 ◽

2017 ◽

pp. 4-12

Author(s):

Н.Н. Хлебникова ◽

Н.А. Крупина

Keyword(s):

Forced Swimming Test ◽

Dipeptidyl Peptidase ◽

Dipeptidyl Peptidase Iv ◽

Forced Swimming ◽

Face Validity ◽

Neonatal Exposure ◽

Depressive State ◽

Serum Corticosterone ◽

Old Rats ◽

Swimming Test

В наших предыдущих исследованиях было показано, что ингибитор пролинспецифической пептидазы дипептидилпептидазы-IV (ДП-IV, EC 3.4.14.5) трипептид дипротин А, введенный крысам в 5-18 постнатальные дни, приводит к развитию у крыс подросткового возраста и взрослых животных эмоционально-мотивационных расстройств. Такие расстройства можно рассматривать как модель смешанного тревожно-депрессивного состояния. Однако специальных исследований по валидности данной модели проведено не было. Цель настоящей работы состояла в проверке влияния трициклического антидепрессанта имипрамина (ИМИ) на депрессивноподобное поведение крыс и уровень кортикостерона в сыворотке крови животных на модели смешанного тревожно-депрессивного состояния. Методика. У крыс в возрасте одного и двух мес. определяли уровень тревожности в автоматизированном тесте «Приподнятый крестообразный лабиринт» и оценивали депрессивноподобное поведение в тесте принудительного плавания. ИМИ вводили взрослым животным в течение 10 дней (20 мг/кг/день, интрагастрально). Уровень кортикостерона в сыворотке крови определяли методом твердофазного иммуноферментного анализа. Результаты. Неонатальное действие дипротина А приводило к повышению тревожности у крыс в возрасте 1 мес. Депрессивноподобное поведение обнаружено у животных в возрасте одного и двух мес. ИМИ нормализовал поведение животных в тесте принудительного плавания и снижал уровень кортикостерона в сыворотке крови крыс. Кроме того, ИМИ снижал вес крыс. Заключение. Результаты исследования свидетельствуют в пользу адекватности модели смешанного тревожно-депрессивного расстройства, возникающего у крыс вследствие действия ингибитора ДП-IV дипротина А на второй-третьей неделях постнатального развития, клиническому прообразу заболевания по критериям «внешней схожести», прогностической и конструкционной валидности. Previously, we have shown that the inhibitor of proline-specific peptidase, dipeptidyl peptidase-IV (DP-IV, EC 3.4.14.5), tripeptide diproptin A administered on postnatal days 5-18 induced emotional and motivational disorders in adolescent and adult rats. These disorders can be considered a model of a mixed anxiety-depression-like disorder. However, validation studies of this model are not available. The aim of this work was to test the effect of the tricyclic antidepressant, imipramine (IMI), on depressive-like behavior in rats and the level of serum corticosterone using the model of mixed anxiety-depressive state. Methods. The level of anxiety was assessed by the automated Elevated Plus Maze test and the depressive-like behavior was evaluated by the forced swimming test in one- and two-month old rats. IMI was administered to adult animals for ten days (20 mg/kg a day, intragastrically). Serum corticosterone concentrations were measured using ELISA. Results. The neonatal exposure to diprotin A increased anxiety in one-month old rats. The depressive-like behavior was observed in animals aged one and two months. IMI normalized behavior of animals in the forced swimming test and reduced serum levels of corticosterone. Also, IMI reduced body weight of rats. Conclusion. The results of the study evidenced adequacy of the model of mixed anxiety-depressive state induced by the DP-IV inhibitor, diprotin A, on the second and third postnatal weeks to the clinical prototype of disease according to criteria of face validity, predictive and construct validity.

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