Clonidine induced hyperphagia and weight gain in monkeys

The effect of the -noradrenergic receptor agonist, clonidine, on food intake and weight was examined in ten adult Stumptail macaque monkeys. An intramuscular injection of 0.1 mg/kg of clonidine HCl for seven consecutive days significantly increased food intake from baseline levels throughout treatment. All but two monkeys gained weight during clonidine treatment with seven animals gaining from 5–15% of their original body weight by the end of 1 week.To whom offprint requests should be sent     

Recurrent hypertonic dehydration due to selective defect in the osmoregulation of thirst

A 6-year-old girl with recurrent episodes of hypertonic dehydration was studied. She denied thirst even with a plasma osmolality as high as 421 mosmol/kg. The hypernatremia was associated with an ability to concentrate urine (854 mosmol/kg). Volume expansion with water corrected hypernatremia (162 to 148 mEq/l) and resulted in an increased urine flow and urinary dilution (137 mosmol/kg) because of suppression of endogenousvasopressin (AVP) release (5.1 pg/ml). Hypertonic saline infusion raised the plasma AVP level (25.6 pg/ml) in response to changes in plasma osmolality (305 to 330 mosmol/kg) and led to a maximal urine osmolality of 818 mosmol/kg. With chronic forced fluid intake, the patient maintained a normal resum sodium concentration (range, 135–145 mEq/l) with a urine osmolality as low as 65 mosmol/kg. These findings are consistent with an isolated defect in the osmoregulation of thirst as the cause of the chronic hypertonic dehydration without deficiency in AVP secretion.     

Excessive hypernatremia in a patient with renal amyloid disease

Summary A 24-year-old Italian male presented with a nephrotic syndrome in September 1984. In February 1985 renal biopsy showed amyloid disease with tubular atrophy and interstitial fibrosis. Edema was treated with furosemide, and cholchicine was started. Because he feared side effects of drug therapy, the patient stopped all medication by July 1985. Instead, he decided to restrict severely fluids in order to fight edema. In early November 1985 his family noted he was becoming increasingly lethargic. Two weeks later, on his admission to the hospital, he had a serum sodium concentration of 193 mmol/l and serum osmolality of 397 mosm/kg. Apart from mild mental status changes neurological examination was normal. The fluid deficit was slowly corrected. He was discharged three weeks later with normal serum electrolytes. This case demonstrates that (1) severe hypernatremia can present with mild neurological symptoms and (2) it can be survived provided that it develops slowly and is corrected cautiously.     

Responses to dietary adulterations in rats with zona incerta lesions

Large lesions of the rostral zona incerta (ZI) permanently reduced food and water intake and body weight to about 75% of control levels. When quinine hydrochloride was added to the water supply, the experimental animals exhibited a somewhat greater initial decrease in fluid consumption, but otherwise responded much like control rats to quinine adulteration of both food and water. The ZI animals reduced their fluid intake when water was added to the food supply, in the form of wet mash, while the controls showed no compensation for the auxiliary water. When presented with sucrose solutions, the ZI animals increased their fluid intake, but reduced their mash consumption, to a greater degree than control rats. The experimental animals also showed an exaggerated response in both food and caloric intake to the addition of sucrose to the wet mash.     

特发性高钠血症2例临床分析

特发性（原发性）高钠血症临床少见,表现为渴感减退、持续性高血钠和血渗透压增高。病因为下丘脑、第三脑室底部或鞍区的病变;发病机制为渴感中枢损伤伴ADH释放阈值升高;强制饮水、双氢克尿噻、弥凝治疗有效。     

Aversive effects of vagotomy in the rat: a conditioned taste aversion analysis

Subdiaphragmatic vagotomy suppresses food intake and water intake in normal rats. Since human patients report some nausea and discomfort following vagotomy, the present study assessed the aversive consequences of vagotomy in rats using a conditioned taste aversion paradigm. Rats were given a total subdiaphragmatic vagotomy or sham vagotomy, and were then maintained on either plain water (Vag-Water and Sham-Water groups) or a novel cherry solution (Vag-Cherry and Sham-Cherry groups). When subsequently tested for their water vs. cherry preferences on postoperative days 6, 16, and 26, the Vag-Cherry group displayed a greater aversion to the cherry solution than did the remaining three groups. This result suggests that vagotomy produces visceral malaise in rats which may contribute to the feeding and drinking suppressive effects of the surgery.     

渴感减退而加压素调节正常的慢性高钠血症2例报告及文献复习

目的 探讨渴感减退而加压素调节正常的慢性高钠血症患者的临床特征.方法 回顾性分析北京协和医院2例及联机医学文献检索系统(MEDLINE)收录的3例患者的临床资料.结果 5例患者的临床特征是:①15岁前起病,慢性病程;②无渴感,意识清楚伴生长发育迟滞;③血钠持续重度升高并间歇性加重;④血浆加压素(AVP)水平及其对血浆渗透压刺激反应正常;⑤单纯饮水治疗即可纠正高钠血症.结论 人类司渴感渗透压调节和AVP渗透压调节的神经通路是独立的.此类慢性高钠血症的治疗以单纯补水为主.     

Circumventricular organ origin of domoic acid-induced neuropathology and toxicology

The neuroexcitotoxin, domoic acid, was responsible for an episode of mussel poisoning in Eastern Canada in 1987. Severe neurologic impairment and some deaths occurred. We have characterized the nature of domoate-induced neuropathology in the mouse brain. Domoic acid was administered intraperitoneally at doses of 2, 3 or 7 mg/kg to Swiss-Webster mice. Brains were examined at 0.5, 1, 24, 48 or 72 h postinjection for evidence of damage. Significant pathologic changes occurred only after the largest dose of domoic acid. Damage was confined to circumventricular organs lacking a blood-brain barrier and their environs, including the organon vasculosum of the lamina terminalis, subfornical organ, mediobasal hypothalamus and area postrema. The neural damage induced by domoic acid was evident at as early as 30 min after injection and increased by 60 min postinjection. The loci of domoic acid-induced neuropathological changes accounts for several central and peripheral effects and toxicities observed following systemic domoate treatment, these included gastroduodenal lesions, hypodipsia, analgesia, and blood pressure fluctuations.