The early hypothyroidism impairs central modulation of heart rate in adult ratsстатьяТезисы
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 14 августа 2017 г.
Аннотация:Introduction. The thyroid hormones (TH) deficiency in early ontogeny could cause mental retardation and motor disturbances in adult age. Along with that, it may also affect autonomic nervous system and impair neural heart control. Autonomic consequences of early TH deficiency are underexplored so we investigated the effects of early hypothyroidism on heart nervous control in adult rats.
Materials and Methods. We added propylthiouracil (PTU, 7 ppm) in dam’s drinking water from the 1st gestation day to 14th day after delivery. Further experiments were performed in male offspring (PTU and control groups) aged 10-12 weeks. TH levels were measured by ELISA. We recorded arterial blood pressure (BP) and heart rate (HR) through implanted catheter in the conscious animals and studied cardiac parasympathetic responsiveness in urethane-anesthetized rats.
Results. PTU treatment depressed thyroid function in 2-week-old offspring but at 10-week age T3 and T4 level didn’t differ from the control group. Adult PTU rats demonstrated impaired vagal heart control as was evident from the higher HR level, the smaller tachycardia in response to M-cholinoceptor antagonist methylatropine and the depressed spectral power of respiratory pulse interval oscillation compared with control. The responses to right vagus stimulation and to injection of M-cholinoceptor agonist metacholine showed no between-group differences.
Conclusions. Early hypothyroidism has long-term effect on cardiac vagal activity which is manifested even after normalization of TH levels. Impaired vagal tone is due to alterations in the central part of parasympathetic system.