French sclerotherapy and compression: Practice patterns.

UNLABELLED: Based on the recommendations of experts, and supported by a low level of proof, compression after sclerotherapy is applied all over the world. OBJECTIVE: Investigating the practice of French vascular physicians for sclerotherapy and the use of post-sclerotherapy compression. METHODS: A questionnaire concerning their practices was sent to French vascular physicians through their regional vascular medicine professional development associations. RESULTS: A total of 366 vascular physicians replied to the questionnaire, of whom 63% (229/366) were in private practice, 6% (21/366) in hospitals and 31% (115/366) had a mixed private-hospital practice. Sclerotherapy was practised by 88% (323/366) of them. Two-thirds of the vascular physicians used sclerosing foam and practised sclerotherapy using ultrasound guidance. Less than one-third of the vascular physicians regularly applied compression after sclerotherapy. When compression was applied, it was usually after treatment of saphenous or accessory saphenous veins and, in most cases, medical compression stockings of 15-20 mm Hg were used. With respect to the period recommended for wearing compression, this ranged from 48 h to 1 week for 65% (193/299) of the vascular physicians questioned. CONCLUSION: The great majority of vascular physicians who answered the questionnaire employ ultrasound guidance to perform sclerotherapy and use sclerosing foam. Compression after sclerotherapy is diversely applied in France and does not comply with the recommendations of the French Health Authorities who recommend wearing a stocking of 15-20 or 20-36 mm Hg for a period of 4-6 weeks. Thus, less than one-third of the vascular physicians regularly used elastic compression and when they did, it was usually a medical compression stocking of 15-20 mm Hg, for 1 week or less.

Thermal ablation of saphenous veins is feasible and safe in patients older than 75 years: A prospective study (EVTA study).

OBJECTIVES: To investigate the tolerance and safety of thermal ablation (TA), consisting of radiofrequency or endovenous laser (EVLA) of saphenous veins (SV) in elderly (group 1 ≥75 years), compared with a control group (group 2 <75 years). METHOD: An Observational multicenter-prospective study was conducted, under the aegis of the French and Swiss Societies of Phlebology (18 centers). Ninety patients were included in group 1, 617 in group 2 (mean age 80 years and 53 years; 69% women in both groups), representing 863 SV. Mean trunk diameters were similar in both groups (small SV: 6 mm; great SV: 7 mm). In group 1, comorbidities were more frequent, particularly cardiac insufficiency, diabetes, history of thrombosis, and CEAP clinical class was significantly higher. RESULTS: EVLA was used in 86% of cases. Settings used were similar in both groups for each technique. Only 6% of TA was performed in an operating room for group 1 (14% group 2). Tumescent local anaesthesia (TLA) alone was used in 91% of cases in group 1 (85% group 2). The mean pain score was only 1.6 for the procedure itself (VASP 0-10; 10 max.) and 1.4 for the 10 days following the procedure. Side effects were few, but rate of paraesthesia was higher when general anaesthesia was used (11.8%) compared with TLA alone (2.2%). At three months, 100% of SV was occluded in group 1 (99.5% group 2), with high satisfaction score (9.3/10). CONCLUSION: TA is safe and effective in elderly; it should be performed strictly under TLA to minimize side effects.

[Quality standards for ultrasound assessment of the superficial venous system of the lower limbs. Report of the French Society for Vascular Medicine]. / Standards de qualité pour la pratique des examens écho-Doppler dans l'exploration du réseau veineux superficiel des membres inférieurs. Rapport de la Société française de médecine vasculaire (SFMV).

The quality standards of the French Society for Vascular Medicine for the ultrasound assessment of the superficial venous system of the lower limbs are based on the two following requirements: technical know-how (mastering the use of ultrasound devices and the method of examination); medical know-how (ability to adapt the methods and scope of the examination to its clinical indications and purpose and to rationally analyze and interpret its results). AIMS OF THE QUALITY STANDARDS: To describe an optimal method of examination in relation to the clinical question and hypothesis; to achieve consistent practice, methods, glossary terminologies and reporting; to provide good practice reference points and to promote a high quality process. THEMES OF THE QUALITY STANDARD: The three levels of examination. Their clinical indications and goals. The reference standard examination (level 2) and its variants according to clinical needs. The minimal content of the examination report, the letter to the referring physician (synthesis, conclusion and management suggestions) and iconography. Commented glossary (anatomy, hemodynamics, semiology). Technical basis. Ultrasound devices settings. We discuss of use of Duplex ultrasound for the assessment of the superficial veins of the lower limbs in vascular medicine practice.

European guidelines for sclerotherapy in chronic venous disorders.

AIM: Sclerotherapy is the targeted chemical ablation of varicose veins by intravenous injection of a liquid or foamed sclerosing drug. The treated veins may be intradermal, subcutaneous, and/or transfascial as well as superficial and deep in venous malformations. The aim of this guideline is to give evidence-based recommendations for liquid and foam sclerotherapy. METHODS: This guideline was drafted on behalf of 23 European Phlebological Societies during a Guideline Conference on 7-10 May 2012 in Mainz. The conference was organized by the German Society of Phlebology. These guidelines review the present state of knowledge as reflected in published medical literature. The regulatory situation of sclerosant drugs differs from country to country but this has not been considered in this document. The recommendations of this guideline are graded according to the American College of Chest Physicians Task Force recommendations on Grading Strength of Recommendations and Quality of Evidence in Clinical Guidelines. RESULTS: This guideline focuses on the two sclerosing drugs which are licensed in the majority of the European countries, polidocanol and sodium tetradecyl sulphate. Other sclerosants are not discussed in detail. The guideline gives recommendations concerning indications, contraindications, side-effects, concentrations, volumes, technique and efficacy of liquid and foam sclerotherapy of varicose veins and venous malformations.

In vivo biological effects of foam sclerotherapy.

OBJECTIVES: This study aims to assess by biological markers the in vivo consequences of foam sclerotherapy (FS) of saphenous veins. The secondary objective of this randomised controlled trial (RCT) is to compare results of two randomised groups: with or without post-treatment compression. PATIENTS AND METHODS: Forty patients with incompetent great or small saphenous veins underwent ultrasound-guided FS. Randomisation was conducted immediately after sclerotherapy to two parallel groups, one (CG) with compression stockings and the other (WCG) without compression. A laboratory work-up was done on days 0 (before sclerotherapy), 1, 7, 14 and 28. The studied markers were: fibrinogen, factor VIII, thrombomodulin, thrombin-antithrombin complex, D-dimers, platelet factor 4 and troponin. RESULTS: General data repartition was homogenous for CG and WCG. Twenty patients were included in each group (females 90%; mean age 58 years). On day 28 (D28), the occlusion rate of the veins was 100% in both groups. In all the samples (D0-D28), apart from a moderate D-dimers' increase at D1-D14, no significant biological change was observed in either the WCG or the CG groups. CONCLUSION: In terms of inflammation and coagulation, FS seems to have a minimal effect on peripheral blood, either with or without post-treatment compression and does not appear to have an effect on the myocardial risk.

Foam sclerotherapy of the saphenous veins: randomised controlled trial with or without compression.

OBJECTIVES: This study aims to compare the efficacy and side effects of foam sclerotherapy of the saphenous veins with or without post-treatment compression using graduated elastic stockings. DESIGN: This is a prospective open randomised controlled trial conducted in two centres. PATIENTS AND METHODS: Sixty patients with incompetent great (GSV) or small saphenous veins (SSV) underwent ultrasound-guided foam sclerotherapy. Randomisation was conducted immediately after sclerotherapy to two parallel groups, one (CG) with compression stockings (15-20 mmHg worn during the day, for 3 weeks) and the other (WCG) without compression. Efficacy of sclerotherapy and all of the side effects were assessed, including side effects in the treated region. On days 14 and 28, clinical and duplex ultrasound (DUS) assessments were performed by independent experts. Patients also completed quality of life (QOL), symptom questionnaires and provided satisfaction scores. RESULTS: Five men and 55 women ranging in age from 32 to 78 (mean 57 years) years were included: 29 in the WCG and 31 in the CG group. On day 28, abolition of venous reflux and occlusion of the vein was obtained in 100% of the cases in both groups. The length of the occluded vein was the same in both groups (mean 36 cm for the GSV and 30 cm for the SSV) as was the mean diameter of the occluded vein (5 mm). Symptoms and QOL questionnaires showed equivalent improvement in both groups on day 28 compared to pre-treatment assessments. Side effects were few with no statistical difference between the two groups. Patient satisfaction scores were high in both groups for the outcome of sclerotherapy results, and good or very good for compression in 50% of the CG cases. CONCLUSION: We found no difference between compression and control groups when comparing efficacy, side effects, satisfaction scores, symptoms and QOL. Further studies are required to establish the role of compression in sclerotherapy and to evaluate other compression strategies.

Liquid versus foam sclerotherapy.

OBJECTIVES: A systematic review to compare efficacy and safety of foam (F) sclerotherapy versus liquid (L) sclerotherapy for primary varicose veins of the lower limbs. METHODS: Systematic searches of electronic databases were conducted in April 2009 to identify relevant published studies. Database searches were augmented with abstracts from conference proceedings and electronic and hand searching of journals not consistently indexed in the major databases. RESULTS: For treatment of saphenous veins, six trials (four randomized controlled trials) were considered. Despite containing much less sclerosing agent, F was markedly more effective compared with L, the difference being put at between 20% and 50%. Four studies were included in a meta-analysis showing efficacy of F at 76.8% (95% confidence interval [CI] 71-82) versus L at 39.5% (95% CI 33-46), chi(2) = 60.9740; P < or = 0.0001. For reticular veins and telangiectases, only two comparative trials were found and do not at present provide any conclusive evidence to support the superiority of efficacy of one form over the other. Statistically, the side-effects reported in all the available comparative trials do not differ between F and L forms, even if visual disturbances seem to be more common with F. CONCLUSION: In the treatment of varices of the lower limbs, F shows much greater efficacy compared to L. Concerning the side effects, no statistical significant differences were found between L and F.

Sclerotherapy of varicose veins in patients with documented thrombophilia: a prospective controlled randomized study of 105 cases.

OBJECTIVES: The aim of this study was to assess thrombotic complications following sclerotherapy in thrombophilic patients in combination with thromboprophylaxis, in two randomized arms using low molecular weight heparin (LMWH) or warfarin. Patients and methods This study received approval from the Ethics Committee. A total of 105 patients (81 females, 24 males) ranging in age from 20 to 82 years (mean 50) were selected: 75 with Factor V Leiden mutation, 18 with prothrombin 20210A mutation, 7 with high level of Factor VIII, 5 combinations of these. After randomization, 51 and 54 patients received warfarin and LMWH, respectively. A total of 199 sclerotherapy sessions were performed. Foam was used in 160 treatments. RESULTS: No episodes of symptomatic deep vein thrombosis (DVT) or pulmonary embolism (PE) occurred; no instances of DVT were revealed by ultrasound-monitoring. CONCLUSIONS: This study suggests that in the three most common forms of thrombophilia, sclerotherapy, in combination with thromboprophylaxis, can be performed safely. Prophylaxis with LMWH is easier to use than warfarin.

Endovenous laser procedure in a clinic room: feasibility and side effects study of 1,700 cases.

OBJECTIVES: To assess the feasibility of saphenous veins ablation by laser in a clinic room. To study immediate and short term (1 to 6 months) complications and to pinpoint those that could be directly linked to this environment. Efficacy of the technique should also be documented. METHODS: Retrospective study (22 centres) carried out in France and Switzerland. Patients with insufficiency of great saphenous vein (GSV) or small saphenous vein (SSV). Clinical stages of clinical, [corrected] aetiological, anatomical and pathophysiological classification (CEAP) C2 to C6. Endovenous laser procedures were performed outside an operating theatre, under local anaesthesia and without high ligation. Efficacy criteria: occlusion of the vein and disappearance of the pathological reflux (duplex scan assessment). The side effects and complications were studied. RESULTS: A total of 1703 procedures (1422 patients) were performed; 74% of the patients were women. [corrected] The mean age of the patients was 57. A total of 1394 GSV and 309 SSV were treated (mean diameters 7.2 mm and 6.4 mm, respectively). Overall success level was 97% and mean length of veins treated was 40 cm for GSV and 21 cm for SSV. Energy applied in joules per centimeter was homogenous (mean and median 64 for GSV and 65 for SSV). Complications were rare and 'simple' apart from one pulmonary embolism which occurred 10 days after a GSV procedure, although no deep vein thrombus was found. A total of two infections were observed: one was an infection localized at the site of access and the other was erysipelas. [corrected] CONCLUSION: Except 2 limited infections (0.1%), this large retrospective study of laser procedures performed outside the operating theatre did not reveal any significant specific complications as regards the environment required. The efficacy results were equivalent to those found in the literature. Regarding cost and constraints induced by operating theatre environment, the clinic room should be able to offer an easier and economic alternative option for saphenous veins ablation with laser [corrected]

Side-effects and complications of foam sclerotherapy of the great and small saphenous veins: a controlled multicentre prospective study including 1,025 patients.

OBJECTIVES: Increasing interest in foam sclerotherapy (FS) for saphenous insufficiency has highlighted the need to study the side-effects and complications of this treatment. The aim of this study is to better assess their nature and incidence. METHODS: A multicentre, prospective and controlled study was carried out in which patients treated with FS for great (GSV) and small saphenous veins (SSV) trunk incompetence were included. Immediate untoward events were reported. Duplex ultrasound (DUS) examination was carried out to assess all patients between the eighth and 30th day. In addition, 20% of patients were called by an external auditor. RESULTS: In total, 818 GSV and 207 SSV were treated in 1025 patients in 20 phlebology clinics. Ninety-nine percent of patients were controlled with DUS and non-duplex-checked patients were all called. The saphenous trunk was occluded in 90.3% of patients. Twenty-seven (2.6%) side-effects were reported: migraine (n = 8, 4 with visual disturbance); visual disturbance alone (n = 7); chest pressure alone (n = 7); and chest pressure associated with visual disturbance (n = 5). Eleven thrombo-embolic events occurred: 10 deep vein thrombosis (DVT) but only five in symptomatic patients, and one pulmonary embolism that occurred 19 days following the FS without DVT identified by DUS. One transient ischaemic stroke, with complete clinical recovery in 30 minutes, and one septicaemia with satisfactory outcome were reported as well. CONCLUSION: This study demonstrates in a large sample of patients a low rate of adverse reactions after FS of great and small saphenous trunks. However, but the eventuality of exceptional but more serious complications has to be taken into account in the management of patients. A multicentre study like this one takes into account different practices and reports all possible complications, thus demonstrating the need for a common validated protocol.

Efficacy of polidocanol foam versus liquid in sclerotherapy of the great saphenous vein: a multicentre randomised controlled trial with a 2-year follow-up.

OBJECTIVE: To compare the relative efficacy of polidocanol (Aetoxisclerol, Kreussler, Germany) when used as a foam or liquid in the treatment of saphenous incompetence. MATERIALS AND METHODS: Multicentre, prospective, randomised controlled trial conducted in patients with incompetence of the great saphenous vein (GSV) with a truncal diameter of 4-8 mm. The great saphenous vein was injected using a single injection 2-2.5 ml of either 3% polidocanol or sclerosant foam containing one-fifth 3% polidocanol to four-fifths air (DSS technique). Clinical assessments and duplex ultrasound scanning were performed after 3 weeks and then every 6 months for 2 years. No re-injection was performed irrespective of the immediate result. The main outcome measure was elimination of GSV reflux. RESULTS: Ninety-five patients participated in the study, 47 were randomised to the foam sclerosant group and 48 to the liquid group. No significant difference between the 2 groups was found regarding sex, age, height, weight and saphenous vein diameter. At 3 weeks, complete elimination of reflux was obtained in 17 of the 48 patients (35%) who received liquid sclerotherapy, versus 40 of the 47 subjects (85%) in the foam group (p<0.001, Chi squared). The incidence of immediate venous spasm and the length of the sclerotic reaction, occlusion measured by echography, were significantly greater in the foam group. There was no difference in the incidence of ecchymosis, inflammatory reactions or other side effects. Follow-up of 6, 12, 18 and 24 months confirms our early results published in 2003. In total only 5 patients were lost to follow-up at 2 years (all of them were in foam group). These patients were included in the final outcome analysis as treatment failures (success rates at 2 years: 53% in foam group and 12% in liquid group). CONCLUSION: The sclerosant foam used in this study was more than twice as effective as the liquid from which the foam was prepared.

Comparison of 1% and 3% polidocanol foam in ultrasound guided sclerotherapy of the great saphenous vein: a randomised, double-blind trial with 2 year-follow-up. "The 3/1 Study".

OBJECTIVES: To compare 1% and 3% POL foam in treating the great saphenous vein (GSV) by ultrasound guided sclerotherapy. DESIGN: Multicentre, prospective, randomised, double-blind trial with 2 year-follow-up. PATIENTS AND METHODS: 148 patients with GSV reflux (saphenous trunk diameter 4-8 mm) were randomised to undergo ultrasound guided foam sclerotherapy using either 1% or 3% POL foam in a single session. Foam production was standardised using a sterile disposable syringe kit including sterile air and the Turbofoam machine. Duplex ultrasonography was used to assess the outcome at 3 weeks, 6 months, 1 year, 18 months and 2 years. The main criterion of success was the disappearance of the venous reflux. The length of occlusion of the vein (only measured at 3 week-echography assessment) was a secondary criterion. Side effects were assessed. RESULTS: 74 patients were included in each group. The mean volume of foam injected was 4.4 ml for the 3% group and 4.6 ml for the 1% group. After 3 weeks, reflux was abolished in 96% (71 patients) of the 3% group and 88% (68 patients) of the 1% group (NS). The mean occlusion length of the vein was 38 cm for the 3% group and 34 for the 1% group (NS). After 2-years, reflux was absent in 69% of the 3% group and 68% of the 1% group (NS). 14 patients were lost to follow-up at 2 years. CONCLUSION: This study demonstrates equivalent efficacy for 1% POL and 3% POL foam in sclerotherapy of the GSV where the trunk is less than 8 mm in diameter. These data obtained two years of follow-up confirm our previously reported 6 month-follow-up data published in 2005.

[Foam echosclerotherapy by puncture-direct injection: technique and quantities]. / Echosclérothérapie à la mousse par ponction-injection directe à l'aiguille: technique et doses.

Foam echosclerotherapy by puncture - direct injection (EMPID) is a technique approved by the French Health Authorities for the management of varicose veins. It combines two principles: the injection of a sclerosing agent by echomonitored direct puncture and the use of this sclerosing agent as a foam. The procedure consists of four stages: targeting of the vein to sclerose and selection of the puncture site, venous puncture under echographic guiding, injection of the sclerosing product under complete echographic monitoring, and post-injection control, checking for the impact of the action and the distribution of the foam in the treated vein. First intention indications concern essentially isolated troncular reflux in lesser and great saphena veins and varicose recurrences. In second intention, EMPID is also an alternative to conventional varicose resection surgery. Emphasizing the principle of precaution, we underline the usefulness of a fine, extemporaneous, standardized and reproducible microfoam - high doses, in particular large volumes of foam, are unwarranted since it has been proven that small volumes are as effective. The recommended concentrations are directly linked to the maximal diameter of the saphena trunks targeted. The volume of foam to be injected must be determined on an individual basis and depends on the presence or not of post-injection spasm, the degree of venous filling and the endothelial impregnation of the treated varicosity (which can be easily monitored because of the spontaneous visualization of the foam producing a tracing effect on the ultrasound); it should not exceed 7.5 ml per session. Apart from the classical side effects due to the liquid form, the foam presents its own, very rare, side effects consisting of minor, constantly and spontaneously reversible, eye disorders. The foam is contraindicated for patients suffering from migraine due to higher incidence of such visual disorders. EMPID is an outpatient procedure for the treatment of varicosities which requires considerable operator skill. This technique cannot be proposed on a large scale without proper and specific training.

Reconstitution of synaptic vesicle biogenesis from PC12 cell membranes.

Neuroendocrine PC12 cells contain small microvesicles that closely resemble synaptic vesicles in their physical and chemical properties. Two defining characteristics of synaptic vesicles are their homogeneous size and their unique protein composition. Since synaptic vesicles arise by endocytosis from the plasma membrane, nerve terminals and PC12 cells must contain the molecular machinery to sort synaptic vesicles from other membrane proteins and pinch off vesicles of the correct diameter from a precursor compartment. A cell-free reconstitution system was developed that generates vesicles from PC12 membrane precursors in the presence of ATP and brain cytosol and is temperature dependent. At 15 degrees C, surface-labeled synaptic vesicle proteins accumulate in a donor compartment, while labeled synaptic vesicles cannot be detected. The block of synaptic vesicle formation at 15 degrees C enables the use of the monoclonal antibody, KT3, a specific marker for the epitope-tagged synaptic vesicle protein, VAMP-TAg, to label precursors in the synaptic vesicle biogenesis pathway. From membranes labeled in vivo at 15 degrees C, vesicles generated in vitro at 37 degreesC had the sedimentation characteristics of neuroendocrine synaptic vesicles on glycerol velocity gradients, and excluded the transferrin receptor. Therefore, vesiculation and sorting can be studied in this cell-free system.

Vesiculation and sorting from PC12-derived endosomes in vitro.

Formation of small vesicles resembling synaptic vesicles can be reconstituted in vitro by incubating labeled homogenates of PC12 cells with ATP and two cytoplasmic proteins, AP3 and ARF1 [Faúndez, V., Horng, J.-T. & Kelly, R. B. (1998) Cell 93, 423-432]. To determine whether AP3 was mediating budding from plasma membranes or endosomes the organelle that generated the synaptic vesicles was characterized. The budding activity was enriched in organelles that labeled at 15 degrees C, but not at 4 degrees C, that excluded a marker of plasma membranes and that contained internalized transferrin, indicating that the precursor was an endosome. Vesicles formed from the endosomal precursor in vitro excluded transferrin. We conclude that ARF-mediated vesiculation into synaptic vesicle-sized organelles uses an endosomal precursor and occurs simultaneously in vitro with sorting of synaptic vesicle proteins from other membrane protein constituents of the endosome.

Biogenesis of synaptic vesicles in vitro.

Synaptic vesicles are synthesized at a rapid rate in nerve terminals to compensate for their rapid loss during neurotransmitter release. Their biogenesis involves endocytosis of synaptic vesicle membrane proteins from the plasma membrane and requires two steps, the segregation of synaptic vesicle membrane proteins from other cellular proteins, and the packaging of those unique proteins into vesicles of the correct size. By labeling an epitope-tagged variant of a synaptic vesicle protein, VAMP (synaptobrevin), at the cell surface of the neuroendocrine cell line PC12, synaptic vesicle biogenesis could be followed with considerable precision, quantitatively and kinetically. Epitope-tagged VAMP was recovered in synaptic vesicles within a few minutes of leaving the cell surface. More efficient targeting was obtained by using the VAMP mutant, del 61-70. Synaptic vesicles did not form at 15 degrees C although endocytosis still occurred. Synaptic vesicles could be generated in vitro from a homogenate of cells labeled at 15 degrees C. The newly formed vesicles are identical to those formed in vivo in their sedimentation characteristics, the presence of the synaptic vesicle protein synaptophysin, and the absence of detectable transferrin receptor. Brain, but not fibroblast cytosol, allows vesicles of the correct size to form. Vesicle formation is time and temperature-dependent, requires ATP, is calcium independent, and is inhibited by GTP-gamma S. Thus, two key steps in synaptic vesicle biogenesis have been reconstituted in vitro, allowing direct analysis of the proteins involved.

Long term stimulation changes the vesicular monoamine transporter content of chromaffin granules.

Bovine chromaffin cells cultured for 5 days in the presence of depolarizing concentrations of K+ ions show a decreased number of secretory (chromaffin) granules per cell. These cells were still capable of exocytosis. Their contents in catecholamine and chromogranin A, components of the granule matrix, and cytochrome b561, a major protein of the granule membrane, were decreased to 35, 30, and 50% of control cells, respectively. However, in the same cells, the number of [3H]dihydrotetrabenazine binding sites, a specific ligand of the vesicular monoamine transporter, was increased to 180% of controls. In situ uptake of noradrenaline in permeabilized cells indicated that [3H]dihydrotetrabenazine binding sites were associated with a functional vesicular monoamine transporter. When analyzed by isopycnic centrifugation, these sites cosedimented with catecholamine, chromogranin A, and cytochrome b561, in a peak with a density lighter than that from controls. The composition of this peak suggests that it contains incompletely matured secretory granules, with a 3-5-fold increase in the vesicular monoamine transporter content of this membrane. This increase might indicate that an adaptative process occurs which allows a faster filling of the granules in continuously secreting cells.

Biochemistry and molecular biology of the vesicular monoamine transporter from chromaffin granules.

Prior to secretion, monoamines (catecholamines, serotonin, histamine) are concentrated from the cytoplasm into vesicles by vesicular monoamine transporters (VMAT). These transporters also carry non-physiological compounds, e.g. the neurotoxin methyl-4-phenylpyridinium. VMAT acts as an electrogenic antiporter (exchanger) of protons and monoamines, using a proton electrochemical gradient. Vesicular transport is inhibited by specific ligands, including tetrabenazine, ketanserin and reserpine. The mechanism of transport and the biochemistry of VMAT have been analyzed with the help of these tools, using mainly the chromaffin granules from bovine adrenal glands as a source of transporter. Although biochemical studies did not suggest a multiplicity of VMATs, two homologous but distinct VMAT genes have recently been cloned from rat, bovine and human adrenal glands. The VMAT proteins are predicted to possess 12 transmembrane segments, with both extremities lying on the cytoplasmic side. They possess N-glycosylation sites in a putative luminal loop and phosphorylation sites in cytoplasmic domains. In rat, VMAT1 is expressed in the adrenal gland whereas VMAT2 is expressed in the brain. In contrast, we found that the bovine adrenal gland expressed both VMAT1 and VMAT2. VMAT2 corresponds to the major transporter of chromaffin granules, as shown by partial peptidic sequences of the purified protein and by a pharmacological analysis of the transport obtained in transfected COS cells (COS cells are monkey kidney cells possessing the ability to replicate SV-40-origin-containing plasmids). We discuss the possibility that VMAT1 may be specifically addressed to large secretory granules vesicles, whereas VMAT2 may also be addressed to small synaptic vesicles; species differences would then reflect the distinct physiological roles of the small synaptic vesicles in the adrenal gland.