Prolonged hypotension and ultrastructural changes in sympathetic neurones following guanacline treatment

Inherited metabolic disease: prospects for the future in both basic and clinical research

The birth of a child with an inherited disorder is often the beginning of a life-long problem for the whole family. About 8.5% of paediatric deaths and 4.7% of paediatric hospital admissions are due to autosomal and sex-linked recessive diseases. These figures are likely to be erroneously low because of incomplete ascertainment. The inherited metabolic diseases therefore merit study on economic as well as humanitarian grounds. Investigations of the disorders of purine metabolism have been conducted for more than a century and a half in the borderland between biochemistry and medicine, illuminating both disciplines and reflecting their separate developments. These studies are a general model for work in other branches of human intermediary metabolism. It is hoped that the basic study of the inborn errors or metabolism will expand our knowledge of the defective gene and of its product, the enzyme protein. Clinical studies should aim to improve the prenatal, postnatal and carrier-state diagnosis of these disorders, and to improve their treatment by methods which can be made practicable and generally available at the clinical level. There may be some hope for enzyme replacement in certain circumstances. The prospect for genetic modification at the clinical level is almost infinitely far away, where many would say that is should remain.

The autonomic nervous system and perinatal metabolism

The development of the autonomic nervous system in relation to perinatal metabolism is reviewed with particular attention given to the adipocyte, hepatocyte and the A and B cells of the islets of Langerhans. Adrenergic receptors develop in the B cell independently of normal innervation and by the time of birth, in most species studied, the pancreas, liver and adipose tissue respond appropriately to autonomic signals. Birth is associated with a huge surge in circulating catecholamines which is probably responsible for the early postnatal rise in free fatty acids and glucagon concentrations in plasma. beta-Blocking drugs such as propranolol have an adverse effect on fetal growth and neonatal metabolism, being responsible for hypoglycemia and for impairing the thermogenic response to cold exposure. beta-Mimetic drugs are commonly used to prevent premature labour and may help the fetus in other ways, for example, by improving the placental blood supply and the delivery of nutrients by increasing maternal fat and carbohydrate mobilization.

Current approaches to development of the autonomic nervous system: clues to clinical problems

A number of different approaches to autonomic development utilizing a variety of experimental models and analytical techniques have been outlined. A scheme, which attempts to delineate a series of events involving separate but sometimes overlapping mechanisms, is proposed for the complex process of formation and maintenance of functional autonomic neuroeffector junctions. The relevance of these basic mechanisms of a variety of clinical abnormalities of autonomic function is discussed.

Methods of sympathetic degeneration and alteration

The role of the sympathetic nervous system in health and disease has often been elucidated by inducing changes in, or degeneration of sympathetic neural pathways. Several methods of inducing peripheral lesions have been created from surgical removal, NGF depletion, auto-immune and chemical destruction to novel approaches using immunotoxins and transgenic animals. This review compares these methods in terms of their mechanism and specificity. The advantages and disadvantages of these techniques are discussed.

Sympathetic neuronal destruction in macaque monkeys by guanethidine and guanacline

To determine whether the peripheral sympathetic neurons of subhuman primates are destroyed by guanacline treatment, we treated Macaca fasicularis with 2 or 20 mg/kg of guanethidine, guanacline, or the saturated analog of guanacline (SAG) 5 times per week for 4 or 12 weeks. All monkeys given 20 mg/kg of guanethidine, guanacline, or SAG showed a marked loss of neurons in the ganglia of the peripheral sympathetic nervous system. Treatment of macaques with 2 mg/kg of the guanidinium compounds resulted in patches of small-cell infiltrate, slight neuronal loss, and degenerative alterations in the sympathetic ganglia. Neuronal alterations in sympathetic ganglia of all treated monkeys were accompanied by a prominent heterogeneous infiltrate of mononuclear cells arranged primarily in a perivascular distribution and extending into the ganglionic neuropil. Peripheral sensory ganglia were unaffected. These histological findings are similar to those described in the guanethidine-induced immune-mediated sympathectomy, which has been extensively studied in the rat.

Species and structural specificity of the lipopigment accumulation and neuronal destruction induced by N-(2-guanidinoethyl)-4-methyl-1,2,5,6-tetrahydropyridine (guanacline)

Guanacline, a guanidinium adrenergic neuron blocking agent similar to guanethidine, was studied clinically and experimentally during the late 1960s. Like guanethidine, it has been reported to produce sympathetic neuronal destruction in rats. Unlike guanethidine, it has been reported to produce irreversible sympathetic deficits in man and to produce fluorescent lipopigment in rat sympathetic neurons. Guanacline and its derivative in which the double bond of the tetrahydropyridine ring is reduced (saturated analog of guanacline, SAG) were prepared. Several species were treated chronically with varying doses of guanethidine, guanacline or SAG; the superior cervical ganglia were examined light microscopically for neuronal destruction and for osmiophilic fluorescent lipopigment accumulation. All 3 drugs produced rapid neuronal destruction in rats accompanied by massive small-cell infiltration. In striking contrast, treatment for many weeks with doses up to 100 mg/kg/day produced no small-cell infiltration or apparent neuronal destruction in mice or guinea pigs. The neuronal destruction produced by guanacline and SAG in the rat, like that caused by guanethidine, was prevented by immunosuppression or gamma-irradiation, indicating that all 3 agents produce neuronal destruction in rats by an immune-mediated mechanism. Thus, the ability of the drug to produce sympathectomy is species specific but not drug specific. The opposite was found with respect to fluorescent lipopigment accumulation. Guanacline, but not guanethidine or SAG, produced fluorescent lipopigment in all species examined. Therefore, the double bond of the tetrahydropyridine ring plays a critical role in the production of the fluorescent lipopigment.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipid accumulation in liver, spleen, lungs and kidneys of miniature-pigs after chloroquine treatment

Chronic chloroquine treatment of type-Göttingen miniature-pigs induced lipid accumulation in the liver, spleen, lungs and kidneys. The lipid analyses showed marked quantitative and qualitative differences between the organs. In the liver the lipids affected most were cholesteryl esters and glucosylceramides, which were increased at the most 20 times. Cholesterol and ganglioside concentrations were also increased, though less markedly. The concentration of acidic phospholipids was slightly increased but that of the neutral phospholipids was unaffected. There was a considerable inter-individual variation in the lipid changes. Spleen and lung showed significant increases of all the major lipids. Glucosylceramide was increased more than the other lipids, namely 6-fold in the spleen and 10-fold in the lung. The concentration of acidic phospholipids as well as that of gangliosides was increased by 50% in the spleen and by 100% in the lung. The organ affected least was the kidney, in which only the glycolipids, both acidic and neutral, were significantly increased. Common to all the organs of the chloroquine-treated pigs was the large increase of glucosylceramide, ganglioside CM2 and bis(monoacylglyceryl)phosphate. The ganglioside increase affected all the individual gangliosides and, except for the increased proportion of ganglioside GM2, there were not remarkable changes in the ganglioside pattern in any of the organs.

Effect of prolonged treatment with adrenergic neuron blocking drugs on sympathoadrenal reactivity in rats

The effects of repeated high doses of the adrenergic neuron blocking drug guanethidine or a hexahydropyrazinoindole compound (2-guanyl-1,2,3,10,10a, hexahydro-1,2,a-pyrazinoindole, EMD 21192) (30 mg/kg i.p., 21.5 mg/kg i.p. respectively, equimolar doses) on sympathoadrenal activity were investigated in normotensive adult rats. During treatment for 5 weeks with either guanethidine or EMD 21192 the systemic blood pressure fell steadily. Noradrenaline content in the heart and vas deferens were decreased markedly by guanethidine and to a much less degree by EMD 21192. EMD 21192 markedly lowers the catecholamine content of the adrenal medulla, presumably as a result of inhibition of dopamine-beta-hydroxylase. The plasma catecholamine concentrations reflected the different sites of action of the drugs in the sympathoadrenal system, i.e. guanethidine mainly reduced circulating norepinephrine and dopamine-beta-hydroxylase by more than 50%, whereas EMD 21192 decreased considerably by the total catecholamines (mainly epinephrine) without altering significantly in the plasma norepinephrine. Disappearance or reduction of fluorescent nerve endings in the iris and the heart and a decrease of the intensity of fluorescence in chromaffin cells of the adrenal gland caused by the drugs were consistent with the biochemical alteration. Whereas the repeated doses of guanethidine caused degeneration of sympathetic nerves, destruction of adrenergic neurons was not found after prolonged treatment with EMD 21192.

Guanethidine induced sympathectomy in the adult rat. I. Functional effects following subacute administration

Guanethidine sulphate 5 and 40 mg/kg was administered intraperitoneally to adult rats for 4, 8, 14, and 28 days followed by discontinuation for 1 day, after administration for 28 days and additionally for 8, 14, 29, and 60 days. Under chloralose-urethane anaesthesia the mean arterial blood pressure and the mean heart rate were determined and the response of these parameters to intravenous noradrenaline 3-1600 ng was recorded. The blood pressure was not significantly changed after guanethidine 5 mg/kg, but lowered by 40 mg/kg, the decrease being reversible on discontinuation. The response of both parameters to noradrenaline was increased by guanethidine depending on the dose. The hypersensitivity was partly reversible on discontinuation, but a significantly increased sensitivity of the heart rate to noradrenaline was observed 60 days after discontinuation of guanethidine 40 mg/kg for 28 days. Histologically a profound loss of nerve cells of the superior cervical ganglion was observed following guanethidine 40 mg/kg, whereas no change was observed after 5 mg/kg. The present investigation has demonstrated that guanethidine 5 mg/kg does not induce histological or permanent haemodynamic changes, whereas 40 mg/kg for 28 days result in an incomplete sympathectomy accompanied by a partially irreversible hypersensitivity to noradrenaline. There is no simple relation between the loss of ganglion cells and the haemodynamic changes, and hence the hypersensitivity to noradrenaline is only in part due to the destruction of the postganglionic sympathetic neurone obtained by long term administration of large doses of guanethidine.

Guanethidine induced sympathectomy in the adult rat. II. Functional effects following chronic administration

Guanethidine sulphate in doses of 5 and 40 mg/kg was administered intraperitoneally to adult rats daily for three months followed by discontinuation of administration for one day or three months. Following guanethidine 40 mg/kg a loss of approximately 95% of the nerve cells of the superior cervical ganglion was observed. No changes were observed after 5 mg/kg. The average mean arterial blood pressure (measured under chloralose-urethane anaesthesia) was lowered by 33 and 54 mmHg by guanethidine 40 mg/kg for three months followed by discontinuation for one day and three months respectively. The heart rate was unchanged. Guanethidine 5 mg/kg did not change any of these parameters. The increase in blood pressure and heart rate caused by intravenously administered noradrenaline was greatly enhanced following guanethidine 40 mg/kg, whereas only small changes were observed following 5 mg/kg. Following discontinuation for one day of 40 mg/kg for three months the potency ratios for the mean arterial blood pressure and the mean heart rate were 31 and 21 respectively, after discontinuation for three months 44 and 17 respectively. The potency ratios following guanethidine 5 mg/kg were 1.5 to 2.0. No changes were observed in the weight of the suprarenal glands following guanethidine. The present investigation has demonstrated an almost total chemical sympathectomy by guanethidine 40 mg/kg for three months and a persistent hypersensitivity to noradrenaline even after discontinuation of medication for three months.

Effects of chronic bretylium treatment on the sympathetic neuron and the smooth musculature of the rat

The effects of chronic i.p. injection of high doses of bretylium on sympathetic nerves on the smooth musculature of the vas deferens of adult and newborn rats were examined using fluorescence histochemistry, light and electron microscopy and organ bath physiological techniques. Bretylium treatment caused mitochondrial swelling, loss of cristae and the formation of electron-dense inclusions in the mitochondria of sympathetic neurons. However, neuron degeneration was not observed and fluorescent histochemical appearance of adrenergic neurons was normal. A small transient supersensitivity of the isolated vas deferens of bretylium-treated rats to noradrenaline, but not to acetylcholine, occurred. There was, however, considerable increase in the maximal contractile response to both noradrenaline and acetylcholine. In high calcium concentrations acetylcholine-induced contractions of vasa deferentia from bretylium-treated rats were significantly greater than control; there was no difference in magnitude of noradrenaline-induced contractions.

[Clinical aspects of non-tumorous diseases of the salivary glands]

The vast field encompassed by the non-tumorous diseases of the salivary glands poses difficult problems for their diagnosis and therapy. In order to facilitate comprehension of the pathological processes and the therapeutical possibilities for their treatment, physiological and biochemical aspects of salivary gland function are presented in the introduction. There are also mentioned in detail most of the diagnostic methods clinically applied today and stress is laid on their respective diagnostic values. In contrast to the opinion of many authors, exploratory excision and puncture are shown to be very important diagnostic tools in salivary gland pathology. The specific application of these methods is often the only means for a reliable diagnosis. The classification of the diseases follows Seifert's (1971) proposal. The chronic diseases of the salivary glands are specifically mentioned with the chronic recurrent and the chronic myoepithelial sialoadenitis taking first place. The sialoses are presented in a larger chapter. An attempt was made to correlate clinical and experimental results, to establish working hypotheses concerning the development of sialoses, to suggest therapeutical possibilities and, last not least, to give an idea of the many clinical and patho-anatomical difficulties to be overcome for a satisfactory understanding of such pathological processes. Finally, various forms of salivary gland fistulas and their treatment are mentioned. The long list of references merely gives an approximation of the abundance of publications dealing with the problems of this field.

Sialoadenosis produced by drug-treatment of hypertonicity. II. Experimental studies on the effects of guanethidine (Ismelin) on the submaxillary glands of the rat

48 rats were treated with guanethidine (Ismelin) in order to study the side-effects on the submaxillary glands following application of a routinely used antihypertensive substance. In contrast to guanethidine-treated parotid glands, no retention of alpha-amylase was observed. The amylolytic activities of the glands are decreased both after treatment for 24 hrs and when a 3 week treatment had been followed by a 2 week recuperation period. This decrease of total amylase content runs parallel with alterations in the alpha-isoamylase patterns of the submaxillary glands. Furthermore, gland growth is inhibited by the guanethidine-mediated "pharmacological sympathectomy". We interpret these proteodyschylic changes of the submaxillary glands as a pharmacologically induced peripheral neurogenic sialoadenosis.

[Sialoadenosis produced by drug-treatment of hypertonicity. I. Experimental studies on the effects of guanethidine (Ismelin) on the parotid glands of the rat (author's transl)]

48 rats were treated with the antihypertensive drug, guanethidine; its effects on the parotid glands (alpha-amylase content, protein concentration, and isamylase distribution patterns) were investigated. The treatment significantly increased the amylase activity in the gland extracts as well as the concentration of isoamylases and their specific enzyme activities. Moreover, we found a redistribution of activity between the 4 isoamylases of the parotid glands. The observed changes are the manifestations of a proteodyschylia concomitant with a peripheral neurogenic sialoadenosis. The described alterations are fully reversible within two weeks after discontinuation of the guanethidine application.

Persistent parotid pain due to guanacline

Details are given of 17 patients who developed parotid pain during treatment with guanacline and which persisted after cessation of guanacline for upto five and a half years. These patients are compared with 17 patients who received similar treatment with guanacline and who did not develop parotid pain. There was no significant difference between patients who experienced parotid pain and those who did not with respect to sex, age, clinical diagnosis, blood urea, previous hypotensive therapy or other drugs given concurrently with guanacline. There was a slightly greater association of parotid pain with other side effects and with a larger daily dose of guanacline. It is suggested that persistent parotid pain after guanacline therapy is due to prolonged or permanent selective sympathetic nerve damage in the region of the cervical sympathetic nerve supply to the salivary glands.

The effect of clonidine treatment on the salivary glands of the rat. Results of biochemical and histological investigations

The side-effects of clonidine, dryness of the mouth and parotid pain, as displayed by this clinically frequently used antihypertensive drug prompted us to investigate its effect on the salivary glands of the rat. After daily intraperitoneal injections for 3 weeks clonidine decreased the specific amylase content of the submaxillary glands caused by fall of activity in 2 of the 4 isoamylases. On the other hand, both activity of alpha-amylase and its isoenzyme pattern remained unchanged in the parotid glands as did their histological and histochemical appearance. The lymph nodes situated in front of the submaxillary glands, however, were considerably affected showing large abscesses. In the adjacent glandular parenchyma, round cell infiltrations and, occasionally, acinic cell necroses were observed.