All issues > Volume 14(3); 1971

Original Article

J Korean Pediatr Soc. 1971;14(3):125-162. Published online March 31, 1971.

Experimental studies on the effects of osmotic stimulations upon urine volume in the midbrain

Sung Woo Shin¹

¹Dept, of Pediatrics, Han Il Hospital Dept, of Pediatrics, College of Medicine, Seoul National University

Abstract

Midbrain is regarded as a higher center which controls hypothalamus in general and in water and electrolytes regulations as well. The author observed the changes of urine volume by osmotic stimulations around the midbrain of rabbits. Korean domestic white male rabbits weighing 1. 8 kg. were gavaged with 2% sodium chloride solution, 100 ml 3 times hourly for hydration before experiment. The sites of stimulation in the midbrain were deviced as illustrated in Diagram 1 and 2 and Table 1, so that each site was located 2 mm apart one another in 3 directions. When the urine volume through the indwelling catheter exceeded 4 ml per 5 minutes after hydration, 2% sodium chloride solution 0. 05 ml was injected bilaterally to the planned symmetrical areas by the aids of stereotaxic apparatus and Choi's stereotaxic atlas, and so far urine volume was reduced in those areas, distilled water was injected to see the effects of hypotonic stimulation in the same way as mentioned above. Thus, the following results were obtained as shown in Diagram 3 and Table 24. 1)Rapid and marked reduction of urine volume by 2% sodium chloride injection and also significant increase of its volume by distilled- water injection were observed in the following 6 areas. a) ⑫d'2 i.e.a part of Red nucleus. b) ⑫d3 i.e. a part of Medial geniculate body. c) ⑭2 i.e. between Brachium of inferior colliculus and Medial geniculate body, d) ⑭d'w i.e. lateral edge of Red nucleus. e) ⑯c2 i.e. inside of Brachium of inferior colliculus, f) ⑯d2 i.e. inner edge of Nucleus of lateral lemniscus. These results are considered that the above areas are related to osmoreceptors, have some connections between hypothalamus either directly or indirectly, and or might be a neurosecretory organ.2) Rapid and marked reduction of urine volume by 2% sodium chloride injection and marked reduction or no change of its volume by distilled water injection were observed at the following 14 areas. ⑫cb ⑫c2, ⑫e2, ⑫e'2, ⑭c1, ⑭e1, ⑭c2, ⑭e'2, ⑯e1, ⑯e2, ⑱c1 ⑱d1⑱d2, ⑳d2. Theses results suggest that mechanical stimulations might play some roles rather than acting as osmotic effectors. 3)No remarkble change of urine volume was observed by the osmotic stimulations in the rest of 39 areas

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