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2.
J R Coll Physicians Edinb ; 37(2): 155-72, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17993085

ABSTRACT

Sir Robert Christison was a professor of Medicine in Edinburgh for 50 years, and twice President of the Royal College of Physicians there. Despite this, few modern descriptions and assessments of either him or his work have been published. In particular, his major work in the field of renal disease, which allows him to be considered one of the fathers of nephrology, has been almost completely forgotten, even in Scotland. In this paper, Christison and his work in renal disease are described, trying to place his sometimes apparently paradoxial views and actions as a physician in the context of a man who lived across major changes in medicine.


Subject(s)
Nephrology/history , History, 19th Century , Humans , Kidney Diseases/history , Scotland
3.
Nucleosides Nucleotides Nucleic Acids ; 25(9-11): 1071-5, 2006.
Article in English | MEDLINE | ID: mdl-17065066

ABSTRACT

Renal disease is rare today in classic adult gout, and gout is rare in renal disease--especially in the young. Here we summarise studies in 158 patients from 31 kindreds diagnosed with familial juvenile hyperuricaemic nephropathy FJHN from a total of 230 kindred members studied in Great Britain. Some patients have been followed for up to 30 years, and allopurinol has ameliorated the progression of the renal disease in all 113 surviving members provided: They have been diagnosed and treated sufficiently early. Compliance with allopurinol treatment and diet has been as important as early recognition. Hypertension has been rigorously controlled. The use of oral contraceptives has been avoided, as has pregnancy in any female with a Glomelar Filtration Rate GFR <70 ml/min. The question arising is: Why is FJHN the most prevalent genetic purine disorder diagnosed in Britain? Is it a lack of awareness which needs to be improved Europe-wide?


Subject(s)
Nephritis, Hereditary/epidemiology , Nephritis, Hereditary/genetics , Purine-Pyrimidine Metabolism, Inborn Errors/epidemiology , Purine-Pyrimidine Metabolism, Inborn Errors/genetics , Adolescent , Adult , Allopurinol/therapeutic use , Child , Disease Progression , Family Health , Female , Glomerular Filtration Rate , Humans , Kidney Diseases/diagnosis , Kidney Diseases/epidemiology , Male , Nephritis, Hereditary/diagnosis , Pedigree , Purine-Pyrimidine Metabolism, Inborn Errors/diagnosis , Time Factors , United Kingdom
4.
J Nephrol ; 19 Suppl 10: S75-87, 2006.
Article in English | MEDLINE | ID: mdl-16874718

ABSTRACT

Until the early nineteenth century, diabetes mellitus was regarded as a disease of the kidney, in which there was an increase in the volume of urine and a wasting of the flesh. With the identification of glucose in blood and urine in the late eighteenth century, first it was re-framed as a disease of assimilation and only then became a metabolic disorder. Whilst these changing concepts were debated, it was noted in parallel that diabetics might show coagulable urine containing albumin, even before Bright and others had established this as a sign of kidney disease. Wilhelm Griesinger (1817-1868) was perhaps the first to suggest in 1859 that the diabetes might be causing the Bright's disease, with the latter as a 'complication'. During the next half-century the observation that as albuminuria appeared and increased, so glycosuria improved or might remit, with a parallel or subsequent evolution into uraemia. Glomerulosclerosis and arteriolosclerosis were described in occasional patients during the same period, but text-books of pathology ignored these observations. Thus it was only when diabetics began to survive longer using insulin treatment in the early 1920s that a diabetic nephropathy became widely recognized. After a few isolated descriptions which were ignored, the now famous paper of Paul Kimmelstiel and Clifford Wilson appeared in 1935 detailing nodular renal lesions in just 8 maturity-onset (48-68 year old) diabetics. They barely noted the association with diabetes however, and it was Arthur Allen in 1941 who clarified the association in 105 patients with diabetes, again all aged over 40. Despite the age of the patients in these early studies, diabetic nephropathy became thought of as a disease of young diabetics as a cohort of survivors of juvenile diabetes passed 15 years or more of disease and more than half developed nephropathy. In the 1950s the technique of renal biopsy was rapidly applied to the study of diabetics, and the early lesions defined using electron microscopy as well as optical methods. Then the role of diabetic nephropathy as a cause of renal failure changed: to begin with numbers of young insulin-requiring diabetics were small and infrequently referred for dialysis treatment or transplantation. Then in the 1970s and 1980s the proportion of such juvenile-onset diabetics developing renal failure gradually fell, but at the same time much larger numbers of older diabetics survived their vascular disease and required treatment for renal failure. World-wide, today diabetes accounts for 20-50% of patients entering established renal failure programs, and absolute numbers increase as greater longevity and western-style living has promoted an 'epidemic' of diabetes at all ages.


Subject(s)
Diabetic Nephropathies/history , Albuminuria/etiology , Diabetic Nephropathies/etiology , Diabetic Nephropathies/pathology , Diabetic Nephropathies/prevention & control , History, 18th Century , History, 19th Century , History, 20th Century , Humans , Kidney/pathology , Kidney Failure, Chronic/etiology , Proteinuria/etiology
6.
QJM ; 95(9): 597-607, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12205338

ABSTRACT

BACKGROUND: The efficacy of allopurinol in autosomal dominant familial juvenile hyperuricaemic nephropathy (FJHN) has been disputed. AIM: To address this question, in the absence of controlled trials. DESIGN: Retrospective long-term follow-up study. METHODS: All kindreds were biochemically screened. Measurements included uric acid clearance, creatinine clearance, serum creatinine, and glomerular filtration rate (GFR). We used five siblings who had died or progressed to transplantation, ten other deceased relatives, and two index cases (one untreated, one non-compliant) as controls to assess the effects of allopurinol. RESULTS: Of eight families with FJHN, six had a strong history of renal disease and early parental death (mean age 41 years, n=10). Of 27 patients started immediately on allopurinol and treated uninterruptedly, 21 responded well, including three children born subsequently. Eight siblings (mean age 19 years) with a normal plasma creatinine at start (<120 micromol/l, mean GFR 80 ml/min/1.73 m(2)) retained stable renal function (mean 14.5 years, mean age 34 years, GFR 85 ml/min/1.73 m(2)). Of the 13 other responders, treated for up to 34 years, 10 with a creatinine <200 micromol/l at diagnosis (mean age 28 years, mean creatinine 137 micromol/l at start) now have a mean creatinine of 210 micromol/l. In contrast, five patients (mean age 26 years) with a creatinine >200 micromol/l (GFR <35 ml/min/1.73 m(2)) when allopurinol commenced, plus one untreated index case, all progressed rapidly (mean 6 years) to end-stage renal failure. In two others (one non-compliant, one initially untreated), GFR fell by >50% in 7 years. Introduction of allopurinol in the latter has stabilized GFR. DISCUSSION: Allopurinol reduced the morbidity and mortality from renal failure seen in untreated siblings and previous generations of these families. Early diagnosis of FJHN is important, so that treatment can begin before irreversible renal damage has developed.


Subject(s)
Allopurinol/therapeutic use , Gout Suppressants/therapeutic use , Kidney Diseases/drug therapy , Uric Acid/blood , Uricosuric Agents/therapeutic use , Adolescent , Adult , Child , Female , Follow-Up Studies , Humans , Kidney Diseases/complications , Kidney Diseases/genetics , Male , Pedigree , Renal Insufficiency/etiology , Renal Insufficiency/prevention & control , Retrospective Studies , Syndrome , Treatment Outcome , Uremia/drug therapy , Uremia/genetics
7.
Int Urol Nephrol ; 33(1): 157-65, 2002.
Article in English | MEDLINE | ID: mdl-12090324

ABSTRACT

Many patients with idiopathic membranous nephropathy are elderly, but little is known about the natural or treated history of these patients. We have studied a cohort of 155 patients with membranous nephropathy who were recruited and followed-up over a 20 year period. We have compared the clinical features and outcome of the older (>60 years) and younger age groups. There was a higher incidence of an identifiable cause for the nephropathy in older patients. At presentation with idiopathic disease, older patients were more often hypertensive and had worse renal impairment than the younger cohort, but had a similar levels of proteinuria, hypoalbuminemia and hematuria. Thrombotic complications and minor rheumatological complaints were more common in the older patients. Prognosis for life and renal survival was worse in the older onset patients. Treatment was well tolerated in selected older patients and was associated with a better outcome in those selected for treatment.


Subject(s)
Glomerulonephritis, Membranous/pathology , Glomerulonephritis, Membranous/therapy , Kidney Failure, Chronic/pathology , Kidney Failure, Chronic/therapy , Nephrotic Syndrome/pathology , Nephrotic Syndrome/therapy , Adrenal Cortex Hormones/administration & dosage , Adult , Age Distribution , Aged , Aged, 80 and over , Biopsy, Needle , Cohort Studies , Confidence Intervals , Disease Progression , Female , Glomerulonephritis, Membranous/mortality , Humans , Incidence , Kidney Failure, Chronic/mortality , Male , Middle Aged , Nephrotic Syndrome/mortality , Probability , Prognosis , Renal Dialysis , Retrospective Studies , Risk Factors , Severity of Illness Index , Sex Distribution , Survival Analysis , Treatment Outcome
8.
Pediatr Nephrol ; 16(8): 680-5, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11519902

ABSTRACT

Today in developed countries the majority of paediatric patients in hospital units suffer from conditions which will continue into adult life, and paediatric nephrology is no exception to this. Despite its obvious importance, the problem of the transition of these children with continuing renal diseases from paediatric to adult clinics is little discussed and often timed and managed badly, with failures on the part of both paediatricians and internists. However, a number of simple principles and actions can help to make the transition more successful and avoid medical and psychological harm. Nephrology can learn from the similar experience in other areas of paediatrics and medicine, such as diabetes, congenital heart disease and cystic fibrosis. Access to facilities for adolescent medicine remains limited and needs to be expanded. Whilst the management of those clearly needing continued care remains paramount, in addition guidelines for the follow-up management of apparently well young adults following attacks of conditions such as Henoch-Schonlein purpura, the haemolyticuraemic syndrome and acute renal failure are needed.


Subject(s)
Aging , Continuity of Patient Care , Kidney Diseases/therapy , Nephrology/methods , Pediatrics/methods , Child , Humans
9.
Proc Natl Acad Sci U S A ; 98(5): 2832-6, 2001 Feb 27.
Article in English | MEDLINE | ID: mdl-11226326

ABSTRACT

The development of functional Ca(2+)-activated K(+) channels (K(Ca)) in chick ciliary ganglion (CG) neurons requires interactions with afferent preganglionic nerve terminals. Here we show that the essential preganglionic differentiation factor is an isoform of beta-neuregulin-1. beta-Neuregulin-1 transcripts are expressed in the midbrain preganglionic Edinger-Westphal nucleus at developmental stages that coincide with or precede the normal onset of macroscopic K(Ca) in CG neurons. Injection of beta-neuregulin-1 peptide into the brains of developing embryos evoked a robust stimulation of functional K(Ca) channels at stages before the normal appearance of these channels in CG neurons developing in vivo. Conversely, injection of a neutralizing antiserum specific for beta-neuregulin-1 inhibited the development of K(Ca) channels in CG neurons. Low concentrations of beta-neuregulin-1 evoked a robust increase in whole-cell K(Ca) in CG neurons cocultured with iris target tissues. By contrast, culturing CG neurons with iris cells or low concentrations of beta-neuregulin-1 by themselves was insufficient to stimulate K(Ca). These data suggest that the preganglionic factor required for the development of K(Ca) in ciliary ganglion neurons is an isoform of beta-neuregulin-1, and that this factor acts in concert with target-derived trophic molecules to regulate the differentiation of excitability.


Subject(s)
Calcium/metabolism , Neuregulin-1/physiology , Neurons/metabolism , Parasympathetic Nervous System/metabolism , Potassium Channels/physiology , Animals , Base Sequence , Chick Embryo , Coculture Techniques , DNA Primers , DNA, Complementary , Neuregulin-1/genetics , Parasympathetic Nervous System/cytology , Parasympathetic Nervous System/embryology , Potassium Channels/metabolism , RNA, Messenger/genetics , RNA, Messenger/metabolism
10.
J Neurophysiol ; 84(6): 2767-76, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11110807

ABSTRACT

The intrinsic electrical properties of identified choroid and ciliary neurons of the chick ciliary ganglion were examined by patch-clamp recording methods. These neurons are derived from a common pool of mesencephalic neural crest precursor cells but innervate different target tissues and have markedly different action potential waveforms and intrinsic patterns of repetitive spike discharge. Therefore it is important to determine whether these cell types express different types of plasma membrane ionic channels, and to ascertain the developmental stages at which these cell types begin to diverge. This study has focused on large-conductance Ca(2+)-activated K(+) channels (K(Ca)), which are known to regulate spike waveform and repetitive firing in many cell types. Both ciliary ganglion cell types, identified on the basis of size and somatostatin immunoreactivity, express a robust macroscopic K(Ca) carried by a kinetically homogeneous population of large-conductance (BK-type) K(Ca) channels. However, the kinetic properties of these channels are different in the two cell types. Steady-state fluctuation analyses of macroscopic K(Ca) produced power spectra that could be fitted with a single Lorentzian curve in both cell types. However, the resulting corner frequency was significantly lower in choroid neurons than in ciliary neurons, suggesting that the underlying K(Ca) channels have a longer mean open-time in choroid neurons. Consistent with fluctuation analyses, significantly slower gating of K(Ca) channels in choroid neurons was also observed during macroscopic activation and deactivation at membrane potentials positive to -30 mV. Differences in the kinetic properties of K(Ca) channels could also be observed directly in single-channel recordings from identified embryonic day 13 choroid and ciliary neurons. The mean open-time of large-conductance K(Ca) channels was significantly greater in choroid neurons than in ciliary neurons in excised inside-out patches. The developmental expression of functional K(Ca) channels appears to be regulated differently in the two cell types. Although both cell types acquire functional K(Ca) at the same developmental stages (embryonic days 9-13), functional expression of these channels in ciliary neurons requires target-derived trophic factors. In contrast, expression of functional K(Ca) channels proceeds normally in choroid neurons developing in vitro in the absence of target-derived trophic factors. Consistent with this, extracts of ciliary neuron target tissues (striated muscle of the iris/ciliary body) contain K(Ca) stimulatory activity. However, K(Ca) stimulatory activity cannot be detected in extracts of the smooth muscle targets of choroid neurons.


Subject(s)
Ganglia, Parasympathetic/metabolism , Neurons/metabolism , Potassium Channels, Calcium-Activated , Potassium Channels/metabolism , Animals , Calcium/metabolism , Calcium/pharmacology , Cell Size , Cells, Cultured , Chick Embryo , Choroid/chemistry , Choroid/embryology , Choroid/innervation , Ciliary Body/chemistry , Ciliary Body/embryology , Ciliary Body/innervation , Dose-Response Relationship, Drug , Ganglia, Parasympathetic/cytology , Ganglia, Parasympathetic/embryology , Ion Channel Gating/drug effects , Large-Conductance Calcium-Activated Potassium Channels , Membrane Potentials/drug effects , Membrane Potentials/physiology , Neurons/classification , Neurons/cytology , Patch-Clamp Techniques , Potassium/metabolism , Potassium/pharmacokinetics , Tissue Extracts/pharmacology
11.
Am J Kidney Dis ; 36(2): 301-9, 2000 Aug.
Article in English | MEDLINE | ID: mdl-10922308

ABSTRACT

In the United States, blacks are more frequently diagnosed than whites with end-stage renal failure (ESRF) from primary hypertension or diabetic nephropathy. We performed a validation retrospective case-note study of all blacks with ESRF who started renal replacement therapy (RRT) at three teaching hospitals in London, England, during 1991 to 1995 to investigate and validate the causes of primary renal disease using standard criteria. We identified 144 black patients with a mean age of 52.0 +/- 16.0 (SD) years; 59% were men and 32% had renal histological data. One hundred forty-four whites who were matched for age, sex, and onset of RRT (42% with renal histological data) underwent a similar validation exercise. Before the validation, the principal working diagnosis in the black patients had been diabetic nephropathy in 35% (89%, type 2; 11%, type 1); primary hypertension, 19%; glomerulonephritis (GN), 18%; and uncertain cause, 15%. After validation analysis, this changed to diabetes, 38% (16% biopsy proven); uncertain, 24%; GN, 20%; and primary hypertension, only 10% (28% biopsy proven). Among the uncertain cases (n = 34), 19 patients had hypertension, but this could not be established as the primary disease; 94% of all blacks had hypertension, accelerated in 21%. Among whites, only 3.5% had primary hypertension, and this proportion was not changed by the validation study. Type 2 diabetes is the most common single cause of ESRF in black patients in London, and although hypertension is more common and more severe in blacks, the proportion of renal failure attributed to primary hypertension is overestimated, and the diagnosis is often made using inadequate criteria.


Subject(s)
Black or African American , Kidney Failure, Chronic/ethnology , Renal Replacement Therapy , Black People , Diabetic Nephropathies/complications , Diabetic Nephropathies/ethnology , Female , Humans , Hypertension/complications , Hypertension/ethnology , Kidney Failure, Chronic/etiology , Kidney Failure, Chronic/therapy , London , Male , Middle Aged , Nephritis/complications , Nephritis/ethnology , Retrospective Studies
13.
Am J Physiol Regul Integr Comp Physiol ; 278(6): R1535-44, 2000 Jun.
Article in English | MEDLINE | ID: mdl-10848521

ABSTRACT

We studied the mechanical and electrophysiological properties of ventricular myocardium from rainbow trout (Oncorhynchus mykiss) in vitro at 4, 10, and 18 degrees C from fish acclimated at 10 degrees C. Temperature alone did not significantly alter the contractile force of the myocardium, but the time to peak tension and time to 80% relaxation were prolonged at 4 degrees C and shortened at 18 degrees C. The duration of the action potential was also prolonged at 4 degrees C and progressively shortened at higher temperatures. An alteration of the stimulation frequency did not affect contraction amplitude at any temperature. Calcium influx via L-type calcium channels was increased by raising extracellular calcium concentration (¿Ca(2+)(o)) or including Bay K 8644 (Bay K) and isoproterenol in the bathing medium. These treatments significantly enhanced the contractile force at all temperatures. Calcium channel blockers had a reverse-negative inotropic effect. Unexpectedly, the duration of the action potential at 10 degrees C was shortened as ¿Ca(2+)(o) increased. However, Bay K prolonged the plateau phase at 4 degrees C. Caffeine, which promotes the release of sarcoplasmic reticulum (SR) calcium, increased contractile force eightfold at all three temperatures, but the SR blocker ryanodine was only inhibitory at 4 degrees C. Our results suggest that contractile force in ventricular myocardium from Oncorhynchus mykiss is primarily regulated by sarcolemmal calcium influx and that ventricular contractility is maintained during exposure to a wide range of temperatures.


Subject(s)
Body Temperature/physiology , Calcium/pharmacokinetics , Myocardial Contraction/drug effects , Myocardial Contraction/physiology , Oncorhynchus mykiss/physiology , 3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester/pharmacology , Action Potentials/drug effects , Action Potentials/physiology , Adrenergic beta-Agonists/pharmacology , Animals , Cadmium/pharmacology , Caffeine/pharmacology , Calcium Channel Agonists/pharmacology , Calcium Channel Blockers/pharmacology , Calcium Channels, L-Type/metabolism , Central Nervous System Stimulants/pharmacology , Cold Temperature , Heart Ventricles/drug effects , Isometric Contraction/drug effects , Isometric Contraction/physiology , Isoproterenol/pharmacology , Myocardium/chemistry , Myocardium/metabolism , Nicardipine/pharmacology , Oxygen Consumption/physiology , Patch-Clamp Techniques , Ryanodine/pharmacology , Sarcolemma/chemistry , Sarcolemma/metabolism , Ventricular Function
15.
Kidney Int ; 57(2): 724-34, 2000 Feb.
Article in English | MEDLINE | ID: mdl-10652052

ABSTRACT

The realization of the key role for raised intra-arterial pressure as a pathogenetic agent in hypertension is usually credited to Ludwig Traube, but Traube in his writings gives credit for the idea to a little-known English doctor, William Senhouse Kirkes (1822-1864). Kirkes' main interest was in cardiology and vascular disease, and he gave the first account of embolism from vegetations in infective endocarditis in 1852. Three years later, he published a study of apoplexy in Bright's disease, in which he pointed clearly to the role of raised intra-arterial tension in the causation of arterial disease, a point that had eluded Bright, Johnson, and other contemporaries. Kirkes died at the age of only 42 while working on a book summarizing his work on cardiology and renal disease, and the neglect of his contribution probably resulted from his early death. We have traced his life history from the few available records; as a boy, Kirkes was apprenticed to become a surgeon and only later trained as a physician. We place his contributions within the setting of the development during the 19th century of understanding of the relationship between the kidney, vascular disease, and high blood pressure.


Subject(s)
Hypertension, Renal/history , Nephrology/history , Cardiomegaly/history , Germany , History, 19th Century , Humans
16.
Int Urol Nephrol ; 32(2): 193-201, 2000.
Article in English | MEDLINE | ID: mdl-11229632

ABSTRACT

Recent data show that, despite a long period during which few elderly patients in end-stage renal failure received grafts, there are neither medical nor ethical grounds for avoiding kidney transplantation, at least in those aged under 70 or even 75 years of age. Units in which transplantation in older recipients is routine show a good survival of recipients, and comparable survival of grafts to those placed in younger recipients. This equality of graft survival with age arises because, although death with a functioning graft is more common in the elderly (principally from cardiovascular disease and infections, with malignant diseases becoming more important with time), graft losses from rejection are lower, and so overall outcomes are similar. Long-term patient survival is better, quality of life is improved and treatment is cheaper than in comparable elderly patients maintained on hemodialysis or chronic ambulatory peritoneal dialysis. In terms of allocation to older recipients, this success presents major practical and ethical difficulties given the shortage of cadaver organs. Data do not support the idea of 'age-matching' older or marginal kidneys to older recipients: like their younger counterparts, older recipients do better with organs from younger donors. Living donors can be used successfully even in those over 70, and elderly living donors have a place in the treatment of the elderly. The optimum immunosuppressive regimes for elderly recipients have not been determined, given their poorer immune responsiveness and lower rejection rates compared with younger individuals.


Subject(s)
Kidney Transplantation , Adolescent , Adult , Age Factors , Aged , Graft Rejection/epidemiology , Graft Survival , Humans , Immunosuppression Therapy , Kidney Transplantation/adverse effects , Living Donors , Middle Aged , Patient Selection , Postoperative Complications/epidemiology , Quality of Life , Renal Dialysis , Treatment Outcome
17.
Kidney Int ; 56(5): 1951-61, 1999 Nov.
Article in English | MEDLINE | ID: mdl-10571807

ABSTRACT

BACKGROUND: Percutaneous renal biopsy, based on the use of an aspiration needle and the patient in the sitting position, was first described by Iversen and Brun in 1951. In 1954, Kark and Muehrcke described the use of the cutting Vim-Silverman needle on patients in the prone position, with a substantial improvement in the rate of success. The 1961 CIBA Foundation Symposium on renal biopsy marked the coming of age of this technique. During the 1950s in Italy, several individuals played a part in promoting and developing percutaneous renal biopsy. Because this pioneer work has received insufficient attention, we describe the contributions of Italians to the early introduction of this technique. METHODS: The Italian and international literature about percutaneous renal biopsy of the period 1951 through 1965 was reviewed. In addition, structured interviews with surviving members of the Italian researchers who first used renal biopsy were conducted. RESULTS: The first renal biopsies in Italy were performed in 1951 in Pisa by the group of Ernico Fiaschi (1913-1989). In their hands, renal biopsy became a tool to investigate the pathogenesis of renal diseases in particular, while simultaneously using the early application of immunofluorescence and electron microscopy. In 1954, Pietro Leonardi (1914-1991) and Arturo Ruol (born 1924) introduced renal biopsy in Padova; they used this technique extensively and published one of the first monographs on the subject. In 1957, Vittorio Bonomini (born 1928) introduced renal biopsy in Bologna, and in subsequent years used this technique to focus on the study of pyelonephritis. CONCLUSIONS: Our historical research shows that Italian groups were among the first to use and develop percutaneous renal biopsy both as a clinical tool and an investigative tool. This article gives international credit to their work.


Subject(s)
Biopsy, Needle/history , Kidney/pathology , History, 20th Century , Humans , Italy
20.
Development ; 126(18): 4157-64, 1999 Sep.
Article in English | MEDLINE | ID: mdl-10457024

ABSTRACT

The developmental expression of macroscopic Ca(2+)-activated K(+) currents in chick ciliary ganglion neurons is dependent on an avian ortholog of TGFbeta1, known as TGFbeta4, secreted from target tissues in the eye. Here we report that a different isoform, TGFbeta3, is also expressed in a target tissue of ciliary ganglion neurons. Application of TGFbeta3 inhibits the functional expression of whole-cell Ca(2+)-activated K(+) currents evoked by 12 hour treatment with either TGFbeta1 or beta-neuregulin-1 in ciliary ganglion neurons developing in vitro. TGFbeta3 had no effect on voltage-activated Ca(2+) currents. A neutralizing antiserum specific for TGFbeta3 potentiates stimulation of Ca(2+)-activated K(+) currents evoked by a target tissue (iris) extract in cultured ciliary ganglion neurons, indicating that TGFbeta3 is an inhibitory component of these extracts. Intraocular injection of TGFbeta3 causes a modest but significant inhibition of the expression of Ca(2+)-activated K(+) currents in ciliary ganglion neurons developing in vivo. Further, intraocular injection of a TGFbeta3-neutralizing antiserum stimulates expression of Ca(2+)-activated K(+) currents in ciliary ganglion neurons developing in vivo, indicating that endogenous TGFbeta3 regulates the functional expression of this current. The normal developmental expression of functional Ca(2+)-activated K(+) currents in ciliary ganglion neurons developing in vivo is therefore regulated by two different target-derived isoforms of TGFbeta, which produce opposing effects on the electrophysiological differentiation of these neurons.


Subject(s)
Iris/embryology , Potassium Channels/metabolism , Transforming Growth Factor beta/metabolism , Animals , Calcium/metabolism , Chick Embryo , Culture Techniques , Electrophysiology , Ganglia/metabolism , Gene Expression Regulation, Developmental , Glycoproteins/metabolism , Immune Sera , Iris/metabolism , Neuregulins , Neurons/metabolism , Protein Isoforms , Tissue Extracts , Transcription, Genetic , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/immunology
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