Duodenal infusion of hypertonic solutions elicits osmolality-dependent thermogenesis in urethane-anaesthetized rats. Here we investigated the involvement of the autonomic nervous system, adrenal medulla and brain in the mechanism of this thermogenesis. Bilateral subdiaphragmatic vagotomy greatly attenuated the first hour, but not the later phase, of the thermogenesis induced by 3.6 % NaCl (10 ml kg−1). Neither atropine pretreatment (10 mg kg−1, i.p) nor capsaicin desensitization had any effect on the osmotically induced thermogenesis, suggesting the involvement of non-nociceptive vagal afferents. Bilateral splanchnic denervation caudal to the suprarenal ganglia also had no effect, suggesting a lack of involvement of spinal afferents and sympathetic efferents to the major upper abdominal organs. Adrenal demedullation greatly attenuated the initial phase, but not the later phase, of thermogenesis. Pretreatment with the β-blocker propranolol (20 mg kg−1, i.p) attenuated the thermogenesis throughout the 3 h observation period. The plasma adrenaline concentration increased significantly 20 min after osmotic stimulation but returned to the basal level after 60 min. The plasma noradrenaline concentration increased 20 min after osmotic stimulation and remained significantly elevated for 120 min. Therefore, adrenaline largely mediated the initial phase of thermogenesis, and noradrenaline was involved in the entire thermogenic response. Moreover, neither decerebration nor pretreatment with the antipyretic indomethacin (10 mg kg−1, s.c) had any effect. Accordingly, this thermogenesis did not require the forebrain and was different from that associated with fever. These results show the critical involvement of the vagal afferents, hindbrain and sympathoadrenal system in the thermogenesis induced by osmotic stimulation of the intestines.
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机译:高渗溶液的十二指肠输注在尿烷麻醉的大鼠中引起重量克分子渗透压依赖性热生成。在这里,我们调查了自主神经系统,肾上腺髓质和大脑在这种生热机制中的参与。双边dia下迷走神经迷走神经极大地减弱了由3.6%NaCl(10 ml kg-1)诱导的生热的最初一小时,但没有减弱。阿托品预处理(10 mg kg-1,腹腔注射)和辣椒素脱敏均未对渗透诱导的生热作用有任何影响,表明无伤害性迷走神经传入。肾上神经节尾部的双侧内脏神经支配神经也没有影响,这表明脊柱传入神经和交感神经传出缺乏与主要上腹部器官的结合。肾上腺去髓质大大减弱了生热的初始阶段,但没有减弱。在整个3小时的观察期内,用β受体阻滞剂普萘洛尔(20 mg kg-1,i.p)进行的预处理减弱了生热作用。渗透刺激后20分钟血浆肾上腺素浓度显着增加,但60分钟后恢复至基础水平。渗透刺激后20分钟血浆去甲肾上腺素浓度增加,并在120分钟内保持明显升高。因此,肾上腺素在很大程度上介导了生热的初始阶段,去甲肾上腺素参与了整个产热反应。此外,去脑或用退热消炎痛(10 mg kg-1,s.c)预处理均无任何作用。因此,这种生热不需要前脑,并且与发烧有关。这些结果表明迷走神经传入,后脑和交感肾上腺系统在肠道渗透性刺激引起的生热中起关键作用。
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