颈脊神经节到颈交感神经节的神经纤维联系在颈性眩晕发病中的意义

目的：研究是否存在从颈脊神经节到颈交感神经节的神经联系,探讨颈性眩晕的发病机制。方法：选取新西兰大白兔70只,随机分为上颈椎组（C2、C3脊神经节组）和下颈椎组（C4、C5、C6脊神经节组）以及相应的对照组。根据分组于相应的脊神经节内注入4%荧光金溶液,动物存活4d后,切取颈上、下交感神经节行冷冻切片后进行荧光显微镜下观察。结果：（1）上颈椎组在实验侧的颈上交感神经节内发现有荧光显像,对侧颈上交感神经节及双侧颈下交感神经节内未出现荧光显像。（2）下颈椎组在实验侧的颈下交感神经节内发现有荧光显像,对侧颈下交感神经节及双侧颈上交感神经节内未出现荧光显像。结论：从颈脊神经节至颈交感神经节之间存在神经纤维联系,且具有节段性分布规律。     

脑性瘫痪大鼠颈交感神经阻断后神经症状及肌张力的研究

目的 :探讨交感神经与脑性瘫痪大鼠痉挛肢体的关系。方法 :将30只大白鼠分成3组 ,随机选择一组采用颈总动脉周围交感神经网剥脱切除术 ,另一组采用颈上节交感神经切断术 ,观察术后大鼠上肢神经症状及肌张力的改变。结果 :交感神经阻断后 ,大鼠上肢痉挛症状改善 ,肌张力下降 ,以颈上节交感神经切断组明显。结论 :交感神经阻断 ,不同程度缓解其所支配肌肉的痉挛状态。     

THE NATURAL HISTORY OF EXPERIMENTAL POLIOMYELITIS INFECTION : I. STUDIES ON THE CENTRIFUGAL SPREAD AND ELIMINATION OF VIRUS IN INTRASCIATICALLY INOCULATED RHESUS MONKEYS

1. Eight rhesus monkeys with experimental poliomyelitis following intrasciatic inoculation of "M.V." virus were used to study the extent of virus spread in the central and peripheral nervous systems and the question of its elimination in the nasal secretions. 2. Tests on nasal secretions collected on absorbent cotton plugs daily and continuously from the moment of inoculation to the end of the disease failed to reveal virus. 3. No virus was found in the olfactory bulbs, nasal mucosa, tonsils and adjacent pharyngeal tissue, salivary glands, adrenals, superior cervical sympathetic ganglia, abdominal celiac ganglia, and small intestine. 4. Elimination of virus by the nasal route was not one of the consequences of poliomyelitis infection resulting from invasion of the "M.V." virus by way of a peripheral nerve in rhesus monkeys. 5. No indiscriminate widespread dissemination of virus occurred in the central nervous system of the intraneurally inoculated rhesus monkeys nor did the virus spread outward sufficiently to involve the collateral sympathetic ganglia or the collections of nerve cells in various peripheral tissues. Under certain circumstances, therefore, the presence of virus in these ganglia and tissues may be used as an index to the portal of entry of the virus.     

The effect of lumbar sympathectomy in the spinal nerve ligation model of neuropathic pain.

To evaluate the sympathetic dependency of pain behaviors in an animal model of neuropathic pain, the effect of surgical sympathectomy on the mechanical sensitivity of the hindpaw was examined in rats with L5 spinal nerve ligation. Mechanical sensitivity was determined by measuring foot withdrawal thresholds to mechanical stimulation with von Frey filaments applied to the base of the third or fourth toe. Tight ligation of the segmental L5 spinal nerve led to the development of mechanical hypersensitivity in the hindpaw. The effects of 2 different procedures of surgical lumbar sympathectomy on mechanical hypersensitivity were compared, limited (resection of sympathetic chain/ganglia L2 to L4 segments) and extensive (resection of L2 to L6 segments) sympathectomies. Mechanical hypersensitivity produced by L5 spinal nerve ligation was partially but significantly reduced by both sympathectomy procedures. In a separate group of rats, the L5 spinal nerve was ligated while irritating the neighboring L4 spinal nerve. This procedure produced a lesser degree of mechanical hypersensitivity, and subsequent sympathectomy had no effect on these animals. These data suggest that sympathectomy is effective in this model only when the animals show severe mechanical hypersensitivity.     

Sympathetic Control of Lower Esophageal Sphincter Function in the Cat: ACTION OF DIRECT CERVICAL AND SPLANCHNIC NERVE STIMULATION

The purpose of this study was to determine the effect of direct stimulation of the sympathetic nerves on the lower esophageal sphincter (LES) in the anesthetized cat. Neither unilateral nor bilateral cervical sympathectomy, or splanchnicectomy significantly modified basal LES pressure in animals with intact vagi, or animals having undergone bilateral cervical vagotomy. Electrical stimulation of the cut, peripheral, cervical sympathetic trunk increased mean arterial blood pressure, but had no effect on LES pressure or LES relaxation as induced by vagal stimulation. Stimulation of the central end of the cervical sympathetic trunk had no effect on LES pressure. Stimulation of the central end of the cut splanchnic nerve produced a decrease in LES pressure with a maximal response of 69.1+/-16.0% (mean+/-SEM). This inhibitory response was not modified by either propranolol or bilateral cervical vagotomy. Stimulation of the peripheral end of the cut, greater splanchnic nerve gave an increase in LES pressure with a maximal response of 38.2+/-7.19 mm Hg. Guanethidine, in the presence or absence of the adrenal glands, significantly augmented this excitatory response. This response was also slightly increased by phentolamine alone at 10 V, 1 Hz, but was not altered by propranolol. The excitatory response was completely antagonized by atropine or by trimethaphan camsylate. Stimulation of the peripheral end of the splanchnic nerve inhibited LES relaxation as induced by vagal stimulation. The results of this study suggest that: (a) the LES in the cat is not affected by either central or peripheral stimulation of the cervical sympathetic trunk; (b) the central portion of the splanchnic nerve carries an afferent inhibitory response to the LES through yet unknown pathways; (c) the peripheral splanchnic nerve carries an atropine-sensitive excitatory response to the LES; and (d) the splanchnic nerves may modulate LES relaxation as induced by vagal stimulation.     

颈交感神经阻断后脑瘫大鼠上肢肌电图的研究

为在肌电图上观察交感神经阻事痉挛性脑瘫大鼠肢体痉挛状态的改善情况，将３０只大白鼠做成骈挛性脑瘫模型，分成３组，随机选择１组采用颈总动脉周围交感神经网剥脱切除术，另１组采用颈上节交感神经切断术，于术后第８ｄ用ＤＡＮＴＥＣ肌电图仪测量３组大鼠上肢肱三头肌的Ｆ波。     

Evaluation of the permanent sympathectomy produced by the administration of guanethidine to adult rats.

The administration of guanethidine to adult rats has been shown by morphological criteria to destroy sympathetic neurons. The objective of this study was to evaluate by biochemical and functional criteria the degree and permanence of this sympathectomy. Young adult male rats (260-300 g) were injected with saline (controls) or with guanethidine for 5 weeks. The status of the sympathetic nervous system in the animals was evaluated 1, 3 and 6 to 7 months after cessation of treatment. Seven months after cessation of treatment; the activity of tyrosine hydroxylase in the superior cervical ganglia of treated animals was greatly reduced, as were the norepinephrine levels in peripheral tissues. The concentration of epinephrine and the activity of tyrosine hydroxylase in adrenals were not different from controls at any of the times studied. Norepinephrine concentrations in several areas of the central nervous system were unchanged. Increases in blood pressure in response to stimulation of the sympathetic vasomotor outflow in the pithed rat preparation were markedly and permanently reduced in guanethidine-treated animals. Isolated intestinal nerve-muscle preparations from guanethidine-treated animals usually contracted in response to nerve stimulation, rather than relaxing as in controls. The response to stimulation of the hypogastric nerve in vas deferens preparations was reduced 1 month after cessation of treatment. The responses of the vas deferens from guanethidine-treated and control animals were the same 7 months after treatment despite a 93% reduction in norepinephrine concentration. The data demonstrate that the administration of guanethidine to adult rats produces a marked and permanent destruction of the peripheral sympathetic nervous system.     

Effects of sympathectomy in a model of causalgiform pain produced by partial sciatic nerve injury in rats

In a previous report we presented a novel behavioral model of neuropathic pain disorders, produced in rat by a unilateral ligation of about half of the sciatic nerve. The model is characterized by rapid onset of behaviors suggesting spontaneous pain and disordered responses to non-noxious and noxious stimuli. These include reduced withdrawal thresholds to repetitive touch in the partially deafferented skin ('touched-evoked hyperesthesia'), touch-evoked allodynia, reduced withdrawal thresholds to noxious thermal stimuli and exaggerated responses to noxious heat and mechanical stimuli ('thermal hyperalgesia'). Some of these disorders are seen at mirror image sites on the hind limb opposite the lesion. These disorder start within hours after partial nerve injury, last many months and are very similar to causalgia in humans following partial nerve injury. Since sympathetic efferent activity is known to aggravate causalgia in humans and sympathectomy is known to relieve it, we studied the effect of changing sympathetic outflow in the rat model. Reversible sympathectomy was carried out using guanethidine injected intraperitoneally in 3 experiments, each at a different time in relation to the partial nerve injury. We found that: (1) sympathectomy performed several months postoperatively alleviated the sensory disorders bilaterally; (2) sympathectomy prior to nerve injury partially prevented the appearance of thermal hyperalgesia but did not affect hyperesthesia to repetitive touch; and (3) sympathectomy at the time of nerve injury aggravated the sensory disorders during the first few days. As maintenance and production of the sensory disorders in this animal model depended on sympathetic nervous outflow, we conclude that the rats were suffering from a syndrome analogous to sympathetically maintained causalgia in man.     

INFLUENCE OF LIGHT ON THE GROWTH AND MALIGNANCY OF A TRANSPLANTABLE NEOPLASM OF THE RABBIT

An experiment is reported in which an environment of constant and continuous light excluding the shorter ultra-violet rays, and one of constant darkness, have influenced the course and character of a malignant disease of rabbits induced by a transplantable neoplasm. Under the influence of constant light the level of malignancy was observed to be low; under the influence of constant darkness the level of malignancy was somewhat lower than in the control animals living under ordinary indoor light conditions, but the level was not as low as among the animals constantly illuminated. These observations furnish experimental evidence in support of the idea that there is a correlation between the external factor of light on the one hand and the manifestations of an experimental malignant disease on the other.     

刺激猫上矢状窦区硬脑膜诱发三叉神经脊束核尾侧段和上颈髓后角c—fos蛋白的表达

目的：硬脑膜是颅内主要的伤害感受组织，在偏头痛的病理生理机制中起重要作用；c-fos的表达已被作为神经元激活的标记物用于痛觉传导的研究。本工作研究血管性头痛涉及的伤害觉信息的传递。方法：以猫为实验对象，在手术暴露其上矢状窦（SSS）后48h,8h,20h电刺激SSS区硬脑膜，应用免疫组化技术，观察延髓和上颈髓c-fos蛋白（Fos)表达的变化。结果：Fos免疫反应阳性神经元主要位于延髓三叉神经脊束核核尾侧部浅层，C1和后角的Ⅰ、Ⅱ层。在孤束的缝核和中央核及颈髓中央导周围X层也有Fos阳性神经元。4h,8h,20h各组中，假手术对照组动物Fos免疫反应阳性神经元随着手术后时间的延长而减少（P＜0．05）；8h刺激组和20h刺激组Fos阳性神经元较相应区且内假手术对照组明显增多（P＜0．05和P＜0．01），提示刺激SSS区硬脑膜可激活三叉神经二级神经元，后者与血管性头痛涉及的痛觉传入有关；延长手术和刺激间隔的时间可减少非特异刺激因素的影响。结论：猫SSS区硬脑膜刺激的c-fos表达模型可作为研究血管性头痛如偏头痛的病理生理机制及其治疗药物和方法的稳定可靠的动物模型。     

Surgical sympathectomy of the heart in rodents and its effect on sensitivity to agonists

A new procedure for sympathetic denervation of the hearts of rats and guinea pigs is described. Bilateral removal of the inferior and medial cervical ganglia results in almost complete loss of catecholamines from atria and ventricles, disappearance of catecholamine-associated histofluorescence from the region of the sinoatrial node and marked depression of the chronotropic concentration-response curve for tyramine in right atria of both species. Seven days after bilateral sympathectomy, the chronotropic concentration-response curve for isoproterenol is shifted to the left by a factor of 3.3 in the rat and 1.7 in guinea-pig right atria. The chronotropic concentration-response curve for histamine was not shifted by sympathectomy in the guinea-pig right atrium. Inasmuch as the rat atrium does not respond to histamine, similar experiments could not be done in the rat. The inotropic concentration-response curve for isoproterenol in electrically driven left atria was not affected by 7 days of sympathectomy in either species. These results indicate that chronic surgical sympathectomy of the heart can be successfully accomplished in the rat and guinea pig. Such sympathectomy induces a postjunctional supersensitivity in guinea-pig right atria which is qualitatively and quantitatively similar to that described previously for chronic treatment with reserpine. Bilateral surgical sympathectomy provides a valuable tool for future investigations of the cellular basis of supersensitivity in the myocardium.     

STUDIES BASED ON A MALIGNANT TUMOR OF THE RABBIT : IV. THE RESULTS OF MISCELLANEOUS METHODS OF TRANSPLANTATION,WITH A DISCUSSION OF FACTORS INFLUENCING TRANSPLANTATION IN GENERAL.

The results of seven methods of transplantation of a malignant tumor of the rabbit are reported and contrasted with results obtained by intratesticular inoculation. It was found that inoculations made into the brain, the anterior chamber of the eye, and the muscles gave an almost uniform series of takes with the production of comparatively large and vigorously growing tumors. Intracutaneous inoculations were less favorable, while with subcutaneous, intravenous, and intraperitoneal inoculations, a growth was obtained in only 20 to 25 per cent of the animals. In contrast with the malignant course of the disease produced by testicular transplantation, the tumors produced by methods other than intracerebral inoculation were relatively benign. In all cases, the growth was of a purely local character; in some instances, there was invasion of the surrounding tissues with local or regional extension of the growth, but no metastases developed in distant organs. Tumors in the brain soon caused death as a result of pressure, and the ultimate fate of tumors in the eye was not determined, but the growth produced by other methods of local inoculation was of relatively short duration and terminated with spontaneous resolution. It was found that while a good growth could be obtained with material which had been subjected to repeated freezing, thawing, and grinding, the use of cell-free filtrates or desiccated tumor tissue gave negative results. In discussing the experiments reported, it was pointed out that there were three groups of factors which had played important parts in determining the results of transplantation. These were the capacity for growth of the tumor cells, animal resistance, and the advantage given the tumor or the animal by the use of a particular method of inoculation. From an analysis of the results obtained with reference to the operation of these factors, the conclusion was reached that while the quality of malignancy displayed by the tumor was conditioned upon the capacity for growth of the tumor cells, the degree of malignancy exhibited in any given instance was a function of animal resistance which was not entirely specific but corresponded closely with the ability of the animal to meet excess demands arising from other causes and, to this extent, represented an expression of the functional capacity of a mechanism which is concerned primarily with the maintenance of the general animal economy.     

硬脊膜外腔阻滞治疗血栓闭塞性脉管炎的临床研究

目的 :应用硬脊膜外腔阻滞方法观察治疗血栓闭塞性脉管炎的疗效。方法 :选择血栓闭塞性脉管炎I、II期的病人 4 7例 ,随机分为三组 :A组 ,硬脊膜外腔阻滞 ;B组 :腰交感神经节阻滞 ;C组 :坐骨神经阻滞。所用药物为利多卡因和康宁克通A混合液。每周治疗一次、三次为一疗程 ,用视觉模拟评分法 (VAS)测痛记分和肢体温度变化为指标 ,观察疗效。每组在治疗前和治疗后 15、30、4 5分钟 ,分别测定各项指标 ,然后进行统计学处理。结果 :A组VAS治疗前 8.2 5± 1.13,治疗后降至 0 .6 3± 1.18。B组 ,由 8.2 7± 1.14降至 1.2 4± 1.0 6。C组由 8.2 3± 1.12降至 1.2 3± 1.0 5。肢体温度 :A组 ,由治疗前 2 5 .7± 1.13℃升至 2 8.4± 1.17℃。B组 ,由 2 5 .3± 1.4 1℃升至 2 7.9± 1.13℃。C组无变化。A、B组和C组比较P <0 .0 1,差异显著。结论 :血栓闭塞性脉管炎在第I、II期 (以肢体血管功能性改变为主 )用硬脊膜外腔阻滞或腰交感神经阻滞的方法 ,可以使血管舒张 ,增加血流 ,又有镇痛作用 ,可以达到治疗的目的 ;而单纯神经阻滞只起到暂时性镇痛作用 ,对疾病本身无效。     

Glucagon response to hypoglycemia in sympathectomized man.

Hypoglycemia stimulates immunoreactive glucagon (IRG) secretion and increases the activity of the sympathetic nervous system. To ascertain if the augmented alpha cell activity evoked by glucopenia is mediated by the adrenergic nervous system, the glucagon response to insulin-induced hypoglycemia of five subjects with neurologically complete cervical transections resulting from trauma, thereby disrupting their hypothalamic sympathetic outflow, was compared to six healthy volunteers. In addition to clinical neurological evaluation, completeness of sympathectomy was verified by failure to raise plasma norepinephrine levels during hypoglycemia compared to the two- and threefold increase observed in controls. Total IRG response (IRG area above basal 0-90 min) and peak IRG levels achieved were the same in the quadriplegics and the controls. Although the glucagon rise tended to be slower, and the peak levels attained occurred later in the quadriplegic patients than in the controls, this response was appropriate for their sugar decline, which was slower and reached the nadir later than in the control subjects. These observations that the glucagon release during insulin-induced hypoglycemia is normal in subjects whose hypothalamic sympathetic outflow has been interrupted provide strong evidence that the sympathetic nervous system does not mediate the glucagon response to hypoglycemia.     

Effects of purinergic and adrenergic antagonists in a rat model of painful peripheral neuropathy

In previous studies, pain behaviors produced in the spinal nerve ligation rat model of neuropathic pain were partly reduced by surgical lumbar sympathectomy. However, systemic injection of phentolamine, an alpha-adrenoceptor blocker, was not effective in reducing pain behaviors, at least in the Sprague-Dawley strain of rats. This suggests that sympathectomy removes not only adrenoceptor function but also other factors that must contribute importantly to the generation of neuropathic pain behaviors. Since the purinergic substance adenosine 5'-triphosphate (ATP) is known to be co-released with norepinephrine (NE) from the sympathetic nerve terminals, we hypothesized that ATP might be involved in the sympathetic dependency of neuropathic pain. The present study tested this hypothesis by examining the effects of systemic injection of an adrenoceptor blocker (phentolamine), a purinoceptor blocker (suramin), and a combination of these two on behavioral signs of mechanical allodynia in the spinal nerve ligation model of neuropathic pain. The results of the present study showed two novel findings. First, the mechanical hypersensitivity (allodynia) resulting from the L5/6 spinal nerve ligation can be reduced either by sympathetic block accomplished by application of a local anesthetic or by surgical sympathectomy of the L2-L6 sympathetic ganglia. Second, suramin (at 100 mg/kg, i.p.) can reduce mechanical hypersensitivity in neuropathic rats when given in combination with 5 mg/kg of phentolamine. This effect was observed in a subset of neuropathic rats, and the drug responses were consistent in repeated treatments within the animal group. Neither phentolamine nor suramin changed the mechanical sensitivity of neuropathic rats when given alone. The data suggest that the purinergic substance ATP is co-released with NE from sympathetic nerve terminals and these two are together involved, at least in part, in the maintenance of the sympathetically dependent component of pain behaviors in some neuropathic rats.     

THE RELATION OF THE SPINAL CORD TO THE SPONTANEOUS LIBERATION OF EPINEPHRIN FROM THE ADRENALS

1. After section of the spinal cord in cats in the cervical region, as low as the last cervical segment, epinephrin continues to be liberated from the adrenal glands. This liberation has all the characters of the normal secretion with intact central nervous system. It is sustained through the same nerve paths connecting the cord with the adrenals. 2. After section of the cord in the middorsal region the spontaneous liberation of epinephrin from the adrenals is abolished within the limits of detectability by the methods employed (denervated eye reactions of Meltzer, and rabbit intestine and uterus segments). 3. The portion of the cord concerned in the liberation of epinephrin does not appear to extend much below the third thoracic segment. 4. In acute experiments on cats under urethane anesthesia no change in the rate of liberation of epinephrin, which could be detected by the tests employed, was observed when the cord was severed in the cervical region.     

EFFECT OF HOST IMMUNITY TO A FILTERABLE VIRUS (VIRUS III) ON THE GROWTH AND MALIGNANCY OF A TRANSPLANTABLE RABBIT NEOPLASM

Experiments are reported in which were studied the course and character of a transplantable malignant neoplasm in normal rabbits and in rabbits immunized with a filterable virus, Virus III. The disease which developed in immunized rabbits was extremely mild and much less severe than in normal animals. The effect upon the tumor process displayed by Virus III immune rabbits in the direction of diminished malignancy is considered to be entirely non-specific in character, and the suggestion is made that it is accomplished through a more effective resistance of the host.     

INFLUENCE OF LIGHT ON THE GROWTH AND MALIGNANCY OF A TRANSPLANTABLE NEOPLASM OF THE RABBIT : SECOND PAPER.

Experiments are reported in which an environment of constant and continuous light with a wave-length of from 3022 to 5790 Ångström units, supplied by mercury arcs in crown glass, and of constant darkness, have influenced the course and character of a malignant disease of rabbits induced by a transplantable neoplasm. Under the influence of constant light the level of malignancy was lower than in control animals living under ordinary conditions of diffused sunlight. Under the influence of constant darkness the level of malignancy was somewhat lower than in control animals but the effect of this environment was modified by the special character of the disease prevailing at this time. The incidence of bone metastases was unusually high, but it was greatly increased in the rabbits kept in constant darkness. These observations furnish experimental evidence in support of the belief that there is a correlation between the external factor of light and the manifestations of an experimental malignant disease.     

Sympathetic nervous system exclusion following experimental subarachnoid haemorrhage prevents vasospasm in rabbits

BACKGROUND: The objective of this study was to establish whether the exclusion of the effect of the sympathetic nervous system prevents vasospasm of cerebral arteries after experimental subarachnoid haemorrhage in rabbits. METHODS: The effect of sympathetic exclusion on vasospasm was studied in 29 New Zealand rabbits under conditions similar to human subarachnoid haemorrhage: 1. The activity of the sympathetic nervous system was excluded only after subarachnoid haemorrhage. 2. The effect of this exclusion was evaluated on the eighth day after subarachnoid haemorrhage. 3. The single haemorrhage model of experimental subarachnoid haemorrhage was chosen. Four groups of rabbits were investigated. The control group A comprised rabbits without subarachnoid haemorrhage; group B consisted of those with subarachnoid haemorrhage (1 ml autologous blood/kg BW suboccipitally into the cisterna magna); group C included those with subarachnoid haemorrhage and pharmacological sympathetic exclusion by the alpha blocker phenoxybenzamine, and group D was composed of those with subarachnoid haemorrhage and operative sympathetic exclusion by cervical gangliectomy. Changes in the basilar arteries of rabbits were evaluated by computer image analysis, using histologic specimens of vessel walls. A new measuring procedure was developed to assess the intensity of vasospasm; the method has a corrugation coefficient that expresses changes in intimal corrugation. RESULTS: Comparison of control group A and group B in regard of vessel intima corrugation showed significantly less corrugated intima in group A (P = 0.0042). In comparison with group B, corrugation of the vessel intima in group C was less intense after sympathetic exclusion by phenoxybenzamine following subarachnoid haemorrhage (P = 0.00012). In comparison with group B, a reduced corrugation was also found in group D after sympathetic exclusion by upper cervical gangliectomy following subarachnoid haemorrhage (P = 0.0026). CONCLUSIONS: The results of the study suggest that exclusion of sympathetic nervous system activity in rabbits prevents vasospasm in circumstances similar to subarachnoid haemorrhage in man. Thus, the sympathetic nervous system could play a critical role in the development of vasospasm in subarachnoid haemorrhage.     

Biochemical and functional evaluation of the sympathectomy produced by the administration of guanethidine to newborn rats.

The administration of guanethidine to newborn rats has been shown by morphological criteria to destroy sympathetic neurons. Newborn rats were injected with guanethidine (50-100 mg/kg/day for 20 days). Upon maturation (at 10 weeks old), the degree of destruction of the sympathetic nervous system (sympathectomy) was assessed. Marked decreases (80-98%) in the norepinephrine concentration in several tissues (heart, spleen, intestine, mesentery, kidney, uterus, vas deferens) were observed in the guanethidine-treated rats when compared to saline-treated controls. No changes were observed in the epinephrine concentration in the adrenals or in the norepinephrine levels in whole brain. Analysis of brain areas showed no change in the norepinephrine levels in brain stem and cerebrum and a small (18%) decrease in the cerebellum. Stimulation of the sympathetic vasomotor outflow in the pithed rat preparation produced almost no response in guanethidine-treated animals. Periarterial nerve stimulation of the isolated perfused kidney preparation also produced essentially no response in guanethidine-treated animals. Isolated intestinal preparations from guanethidine-treated animals responded to nerve stimulation with contractions rather than relaxation as seen in preparations from control animals. Isolated vas deferens preparations responded normally to nerve stimulation despite a 95% decrease in tissue norepinephrine concentration. These data indicate that administration of guanethidine to newborn rats produces a more complete peripheral sympathectomy, especially of the vasculature, than immunosympathectomy or neonatal administration of 6-hydroxydopamine and does so with no significant effect on central noradrenergic neurons.