Juan Martínez-León

Consorcio Hospital General Universitario de Valencia, Valencia, Valencia, Spain

Are you Juan Martínez-León?

Claim your profile

Publications (41)109.22 Total impact

  • Revista portuguesa de cardiologia : orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of the Portuguese Society of Cardiology. 11/2013;
  • [show abstract] [hide abstract]
    ABSTRACT: Aims In the present study we investigated the intervention of nitric oxide and prostacyclin in the responses to vasopressin of isolated thyroid arteries obtained from multi-organ donors. Main methods Paired artery rings from glandular branches of the superior thyroid artery, one normal and the other deendothelized, were mounted in organ baths for isometric recording of tension. Concentration-response curves to vasopressin were determined in the absence and in the presence of either the vasopressin V1 receptor antagonist d(CH2)5Tyr(Me)AVP (10(-8)M), the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA, 10(-4)M), or the inhibitor of prostaglandins indomethacin (10(-6)M). Key findings In artery rings under resting tension, vasopressin produced concentration-dependent, endothelium-independent contractions. The vasopressin V1 receptor antagonist d(CH2)5Tyr(Me)AVP (10(-8)M) displaced the control curve to vasopressin 19-fold to the right in a parallel manner. The contractile response to vasopressin was unaffected by L-NMMA or by indomethacin. Significance Vasopressin causes constriction of human thyroid arteries by stimulation of V1 vasopressin receptors located on smooth muscle cells. These effects are not linked to the presence of an intact endothelium or to the release of nitric oxide or prostaglandins. The constriction of thyroid arteries may be particularly relevant in certain pathophysiological circumstances in which vasopressin is released in amounts that could interfere with the blood supply to the thyroid gland.
    Life sciences 08/2013; · 2.56 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: INTRODUCTION AND OBJECTIVES: The aim of this study was to compare the in-hospital clinical outcomes of minimally invasive, isolated aortic valve replacement vs median sternotomy. METHODS: Between 2005 and 2012, 615 patients underwent aortic valve replacement at a single institution, 532 by a median sternotomy (E group) and 83 by a J-shaped ministernotomy (M group). RESULTS: No significant differences were found between the E and M groups in terms of age (69.27 [9.31] years vs 69.40 [10.24] years, respectively), logistic EuroSCORE (6.27 [2.91] vs 5.64 [2.17], respectively), size of implanted valve prosthesis (21.94 [2.04] mm vs 21.79 [2.01] mm, respectively), or the incidence of diabetes, hypercholesterolemia, high blood pressure, or chronic obstructive pulmonary disease. Mean cardiopulmonary bypass time was 102.90 (41.68) min for the E group vs 81.37 (25.41) min for the M group (P<.001). Mean cross-clamp time was 77.31 (29.20) min vs 63.45 (17.71) min for the S and M groups, respectively (P<.001). Mortality in the E group was 4.88% (26). There were no deaths in the M group (P<.05). The E group was associated with longer intensive care unit and hospital stays: 4.17 (5.23) days vs 3.22 (2.01) days (P=.045) and 9.58 (7.66) days vs 7.27 (3.83) days (P<.001), respectively. E group patients had more postoperative respiratory complications (42 [8.0] vs 1 [1.2%]; P<.05). There were no differences when postoperative hemodynamic, neurologic, and renal complications, systemic infection, and wound infection were analyzed. CONCLUSIONS: In terms of morbidity, mortality, and operative times, outcomes after minimally invasive surgery for aortic valve replacement are at least comparable to those achieved with median sternotomy. The length of the hospital stay was reduced by minimally invasive surgery in our single-institution experience. The retrospective nature of this study warrants further randomized prospective trials to validate our results. Full English text available from:www.revespcardiol.org/en.
    Revista Espa de Cardiologia 06/2013; · 3.20 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: OBJECTIVES: Increasing degrees of renal impairment are associated with higher rates of morbimortality after coronary artery bypass grafting (CABG). This incremental risk has not been well studied in off-pump procedures (OPCAB). We assessed its impact on OPCAB and on-pump CABG (ONCAB). METHODS: A total of 1769 patients undergoing primary CABG (January 1995 through June 2011) had complete data on glomerular filtration rate (eGFR). 930 patients had Stage 2 renal insufficiency, 330 Stage 3, 27 Stage 4 and 465 normal renal function (Stage 1). Seventeen patients with end-stage disease (Stage 5) were excluded. The OPCAB technique was selectively used in 350 high-risk patients. Preoperative variables and postoperative outcomes were compared among eGFR subgroups and between matched and unmatched OPCAB vs ONCAB groups. RESULTS: Stages 3-4 patients were older (P < 0.0001), with higher prevalence of diabetes (36.8, 35.0, 39.7 and 74.1%, P < 0.01, 1-4 eGFR groups) peripheral arteriopathy (6.0, 9.0, 15.8 and 29.6%, P < 0.0001) and lower left ventricular ejection fraction (LVEF) (GFR-LVEF correlation: Pearson: 0.12, P < 0.0001). On-pump GFR groups had increasingly higher in-hospital mortality (1.0, 1.2, 3.5 and 15.4%, P < 0.0001), but no differences were observed in OPCAB (5.5, 4.8, 5.4 and 7.1%, P = 0.97). Similar trends on in-hospital morbidity were observed in ONCAB vs OPCAB groups: low cardiac output (P < 0.01), pneumonia (P < 0.01) and stroke (P < 0.05). GFR only predicted mortality in ONCAB patients (odds ratio (OR): 0.96, 95% CI: 0.94-0.98; P < 0.01). Patients with higher eGFR stages had statistically more reduced long-term survival, and this pattern was similar in the three treatment groups, also including the OPCAB group, who had the lowest survival in patients with eGFR stage 4. CONCLUSIONS: Patients with low GFR (Stages 3-4) undergoing ONCAB were at increased risk of early morbimortality. In contrast, there were no significant differences in operative morbimortality among eGFR groups in OPCAB patients. This 'off-pump advantage' on early outcomes was not observed at the long-term follow-up.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 02/2013; · 2.40 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Background Etiology and other factors may influence the outcomes of mitral valve repair. We have analyzed survival and durability in a variety of etiologies. Material and Methods 406 patients underwent mitral valve repair (1997–2011) with ages between 19–84 years. 156 were females (38.4%). 57.1% patients were in NYHA class III-IV. 5 groups were considered: degenerative (group-D), 203; ischemic (group-I), 90; functional (non-ischemic) (group-F), 19; rheumatic (group-R), 61 and endocarditis (group-E), 33 patients. Undersized annuloplasty was used in ischemic and functional groups. Quadrangular resection and neochordal repair were predominant in case of degenerative etiology whereas a variety of resective and reconstructive techniques were used in rheumatic and endocarditis groups. Results 30-day mortality was 4.4%: 3.4%, 4.4%, 0%, 6.6% and 10% in respective groups. 5 and 10-year survival: 86 ± 1% and 70 ± 4%. Long-term mortality was higher in groups F and I (31.6% and 20%) compared with 12.3%, 11.5% and 13.3% in groups D, R and E. Group-D had higher durability and freedom from grade 3–4/4 mitral regurgitation than non-degenerative groups: 86 ± 2 vs 84 ± 2% (p = 0.46) at 5 years and 82 ± 3 vs 54 ± 1% (p = 0.02) at later follow-up. Group-R was associated with recurrent grade-3 and grade-4 mitral regurgitation (OR: 1.98, 95%-CI: 1.01–3.89; p = 0.05 and OR: 3.31, 95%-CI: 1.17–9.32; p = 0.02). 14 patients underwent mitral valve replacement: 3, 1, 1, 6 and 3. Conclusions The outcomes of mitral valve repair were successful. Survival, recurrence rate and reoperation were excellent in group-D. Rheumatic regurgitation had shorter durability and functional mitral regurgitation had lower survival.
    Cirugía Cardiovascular. 01/2013; 20(2):65–73.
  • [show abstract] [hide abstract]
    ABSTRACT: Functional mitral regurgitation often is associated with dilated cardiomyopathy, or left ventricular remodeling. Surgical repair result commonly in an annuloplasty ring. We present a case of severe mitral regurgitation due to dilated cardiomyopathy treated with implant of Geoform® annuloplasty ring, with a good immediate outcome, and a successive failure of the annuloplasty due to dehiscence of the ring and requirement of a mitral valve replacement.
    Cirugía Cardiovascular. 01/2013; 20(3):153–155.
  • [show abstract] [hide abstract]
    ABSTRACT: Background The use of neochordal repair has recently increased, not only as a combined procedure with quadrangular resection, but also as an isolated technique. Our aim was to evaluate its impact on the feasibility and outcomes of mitral valve repair. Material and methods A global group of 203 patients underwent valve repair for degenerative mitral regurgitation between 1997-2011. Their mean age was 62 ± 12 years and 36% were females. Complex repair was considered in case of multi-scalloped, bileaflet or commissural prolapse. Two technical subgroups were compared: resection without neochordal repair (Group-A: 140 patients) and neochordal repair without resection (Group-B: 46 patients). Seventeen patients with artificial chordae combined with resection were excluded. Complexity of valvular lesions, early and long-term mortality and repair durability were studied. Results In-hospital mortality was 3.4% (7 patients); 4.3% in Group-A (6 patients) and 2.2% in Group-B (one patient). Five and 10-year survival was 89 ± 2% and 77 ± 4%. At follow-up (58 ± 42 months), 22 patients from Group-A (15.7%) and 2 from Group-B (4.3%) died. The recurrence of grade 3-4/4 mitral regurgitation in Group-B versus Group-A was 1 (2.2%) versus 20 (14.3%); P < .05. Sixty five patients (32.0%) underwent complex repairs, especially from Group-B: 27 (58.7%) vs 27 (19.3%), P < .0001. This group had a higher incidence of multi-scalloped prolapse (mean number of segments): 1.80 ± 0.80 vs 1.20 ± 0.44, P < .0001; anterior leaflet prolapse: 14 (30.4%) vs 14 (10.0%), P < .01, and multiple chordal rupture: 24 (52.2%) vs 29 (20.7%), P < .0001. Conclusions Neochordal repair showed excellent mid-term results with significant increase of repair feasibility. Its use as an isolated procedure has been really effective in patients with more extensive and complex lesions
    Cirugía Cardiovascular. 01/2013; 20(3):130–138.
  • Mayte Ballester, Julio Llorens, Juan Martinez-Leon
    European Journal of Anaesthesiology 06/2012; 29(6):297-298. · 2.79 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Myocardial oxidative stress plays an essential role in the pathogenesis of ischaemia-reperfusion injury associated with coronary artery bypass grafting (CABG). Both propofol and volatile anaesthetics have been shown to reduce reactive oxygen species in experimental and clinical studies. To compare the influence of sevoflurane and propofol on myocardial oxidative stress markers (F2-isoprostanes and nitrates/nitrites) in coronary sinus blood samples from patients undergoing off-pump CABG. Randomised controlled clinical study of patients scheduled for off-pump CABG in a tertiary academic university hospital from June 2007 to August 2009. Forty patients consented to enrolment and were assigned to receive either propofol or sevoflurane. Upon completion of the proximal anastomosis, a retroplegia cannula was inserted in the coronary sinus to obtain blood samples, according to the study protocol. Markers of lipoperoxidation (F2-isoprostanes) and nitrosative stress (nitrates/nitrites) were measured in coronary sinus blood samples at three time points: after the end of the proximal anastomosis (T1), after completion of all grafts (T2) and 15 min after revascularisation (T3). Of the 40 recruited patients, 38 fully completed the study. In the sevoflurane group (n = 20), concentrations of oxidative stress markers in the coronary sinus remained almost constant and were significantly lower than those in the propofol group (n = 18) at all time points. F2-isoprostanes concentrations were as follows at T1: sevoflurane group 37.2 ± 27.5 pg ml vs. propofol group 170.7 ± 30.9 pg ml [95% confidence interval (CI) 112.16-155.08, P < 0.0001); at T2: sevoflurane group 31.94 ± 24.6 pg ml vs. propofol group 171.6 ± 29.7 pg ml (95% CI 119.78-159.63, P < 0.0001); and at T3: sevoflurane group 23.8 ± 13.0 pg ml vs. propofol group 43.6 ± 31 pg ml (95% CI 2.87-36.63, P = 0.023). In patients undergoing off-pump CABG, sevoflurane showed better antioxidative properties than propofol.
    European Journal of Anaesthesiology 09/2011; 28(12):874-81. · 2.79 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: The aim of this study was to describe a previously unreported mutation in the SDHD gene, which has been linked to familial paraganglioma. Clinical data were collected from all members of the family, which had four siblings affected with paraganglioma. For the index patient, genomic DNA extraction from whole blood was performed using the High Pure PCR Template Preparation kit. The nucleotide sequence in the index patient revealed a deletion in the SDHD gene, c.165_169 + 14del. The loss of nucleotides in the DNA led to production of an anomalous protein. RNA analysis showed the absence of exon 2 in the sequence that corresponded to the mRNA from the index case. Genetic testing of this deletion was extended to the symptomatic and asymptomatic brothers and sisters of the index patient and other family members at risk. The deletion was detected in both symptomatic brothers, in accordance with their phenotype, but not in the asymptomatic sister. In the other asymptomatic brother (II.7) the deletion was detected and magnetic resonance angiography revealed the vascular characteristics of two tumors in both carotid bifurcations. Thus, we report a novel punctual mutation in the SDHD gene, which is related to familial paraganglioma: the deletion was c.165_169 + 14del.
    Acta oto-laryngologica 05/2011; 131(10):1110-6. · 0.98 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Development of late significant tricuspid regurgitation (TR) after successful mitral valve replacement (MVR) is not infrequent. The impact of different aetiologies or diverse surgical procedures has not been adequately investigated. We studied the influence of subvalvular preservation techniques during MVR on the incidence of late TR. A total of 801 patients with grade ≤ 2+/4+ preoperative TR underwent MVR without associated tricuspid procedures from January 1994 to August 2008. In 595 patients, only posterior mitral leaflet preservation was performed (group A). In the remaining 206 patients, both anterior and posterior leaflets were retained (group B). Postoperative development of significant TR was defined as a TR increase by more than one grade from preoperative or final TR grade ≥ 3+/4+ at follow-up. The global incidence of postoperative significant TR was 8.6%, with higher incidence in females (9.4% vs 6.7%, p=0.12), rheumatic disease (9.7% vs 6.5%, p=0.07), patients with previous AF (11.8% vs 3.8%, p<0.001) and, especially, in group A (10.8% vs 2.4%, p<0.001). The Maze procedure was protective in patients with AF (the incidence with and without associated Maze was 6.7% vs 13.2%, p=0.04). Preoperative left-atrial diameters were higher in patients with postoperative development of TR (56 ± 9 mm vs 51 ± 12 mm, p=0.01). Group A (p=0.04) and preoperative atrial fibrillation (p=0.001) were significant predictors of late postoperative TR. Late functional TR decreased free survival from chronic heart failure. Several clinical and operative factors are associated with the development of significant TR after MVR. Although early surgical intervention for TR may be recommended in selected patients, complete subvalvular preservation of the mitral valve and routine surgical ablation of atrial fibrillation can significantly reduce its incidence.
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 12/2010; 39(6):866-74; discussion 874. · 2.40 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: We present a simple technique for facilitating accurate polytetrafluoroethylene chordal height adjustment in surgical repair of myxomatous mitral valve disease. This approach is based on the annulus as the reference level. The artificial chordae are first fixed to the corresponding papillary muscle. Each chordal pair is then attached to the free edge of the prolapsed leaflet, and subsequently, the leaflet edge is also attached to the adjacent annulus by temporary fixing sutures. As a result, the leaflet is gently folded. Finally, the polytetrafluoroethylene suture is knotted during proper apposition of the free edge of the leaflet to the annulus.
    The Annals of thoracic surgery 05/2010; 89(5):1682-4. · 3.74 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: Purpose To present the initial experience with thoracoscopic approach as a treatment option for lone atrial fibrillation (AF). Methods Between April and October 2007, five patients with symptomatic lone AF underwent a surgical ablation procedure through right thoracoscopic approach, consisting in a circunferential epicardial electric isolation pattern of the four pulmonary veins with a flexible microwave ablation device. Results There were no hospital deaths and the average hospital stay was 4 days. In one patient an in situ conversion to mini-sternotomy was needed. At the end of the follow-up, three patients were again in AF. Conclusions The thoracoscopic ablation surgery is reproducible and has a low morbidity rate. The technology used, unique for this kind of unilateral approaches, did not show the expected effectiveness. We have abandoned this procedure waiting for new technical means.
    Cirugía Cardiovascular. 01/2009; 16(3):235–239.
  • [show abstract] [hide abstract]
    ABSTRACT: Background Although valve repair is the gold-standard in mitral valve regurgitation, durability and reoperation are relevant issues. Several factors may increase the probability of failure. We reviewed our experience addressing these issues. Material and methods Two hundred eighteen patients underwent mitral valve repair from febru-ary-98 to August-07. Their mean age was 62 ± 12 years and 76 (34.9%) were female; 68.8% were in NYHA functional class III-IV. According to the etiology 5 groups were considered: degenerative (group A) with 119 patients, ischemic (group B) with 44, functional non-ischemic (group C) with 14, rheumatic (group D) with 26 and endocarditis (group E) with 15 patients. The main techniques used in group A were: quadrangular resection (83), sliding plasty (8), PTFE-neochordae (16), chordal transposition (8) and edge-to-edge repair (11); in group D: annuloplasty (16), commissurotomy (11), resection-decalcification (5) and edge-to-edge (2) and in group E: perforation closure (9), resection (7) and commissuroplasty (2). Isolated annuloplasty was used in groups B and C. Results Early mortality was higher in groups B, C and E. The global 30-day mortality was 5.9% and only 3 patients died at follow-up. Actuarial survival at 5 years was 97 ± 1% (mean follow-up: 44 ± 29 months), freedom from REDO 91 ± 2% and freedom from recurrent 3+4+ regurgitation at 5 and 10 years: 85 ± 2 and 82 ± 3%. Age (HR: 1.07; IC 95%: 1.01-1.13; p < 0.05) and bileaflet prolapse (HR: 3.71; IC 95%: 1.02-13.45; p < 0.05) were predictors of recurrent regurgitation. Conclusions Degenerative was the most frequent etiology (54%). Survival and durability were excellent in the global group. The higher mortality was 30-day mortality, particularly in ischemic, functional and endocarditis groups.
    Cirugía Cardiovascular. 01/2009; 16(1):23–30.
  • [show abstract] [hide abstract]
    ABSTRACT: Subvalvular preservation is beneficial in patients undergoing mitral valve replacement, especially in degenerative mitral regurgitation. Its feasibility and benefit is less evident in rheumatic disease. Our aim was to study the impact of preservation techniques in rheumatic patients and determine risk factors for mortality. Five hundred sixty-six rheumatic patients undergoing mitral valve replacement between 1996 and 2006 have been included. One hundred fifty-six patients had complete excision of the subvalvular apparatus (group 1), 248 had preservation of the posterior leaflet (group 2), and 162 had total chordal preservation (group 3). Echocardiography was performed preoperatively, at discharge, at 1 year, and at late follow-up. Reduction of ventricular volume was greater in groups 2 and 3, especially if previous mitral regurgitation or mixed disease were present. In mitral stenosis, valve resection caused postoperative increase of volume. Ventricular ejection and pulmonary hypertension had better outcome with valve preservation. Valve resection was associated with late mortality (hazard ratio, 2.64; p < 0.05), and complete chordal preservation was protective (hazard ratio, 0.31; p = 0.13). Actuarial survival (130 months) was better in group 3: 77.18% +/- 0.04%, 85.38% +/- 0.03%, and 93.22% +/- 0.02%, respectively (p < 0.01 group 1 versus group 3). Group 1 exhibited more low cardiac output syndrome (p < 0.01) and more patients in New York Heart Association functional class III and IV at last follow-up: 17.8% versus 3.9% and 2.0% (p < 0.001). Complete chordal preservation is possible in a large percentage of rheumatic patients. Greater decrease of ventricular volume is obtained for mitral regurgitation. In mitral stenosis, subvalvular preservation may avoid postoperative ventricular dilatation. Consequently, ventricular ejection, pulmonary hypertension, and clinical outcomes may improve with time.
    The Annals of thoracic surgery 08/2008; 86(2):472-81; discussion 481. · 3.74 Impact Factor
  • The Journal of thoracic and cardiovascular surgery 06/2008; 135(5):1169-72. · 3.41 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Nowadays atrial fibrillation is usually treated simultaneously with cardiac procedures, and new cryo-systems have been developed for performing easier and faster intraoperative ablation. However, the old cryode designs can still be useful in surgical practice and represent a more cost-effective method. In this article we present a technique using old-fashioned cryodes for intraoperative treatment of atrial fibrillation and comment on its advantages and limitations.
    The Annals of thoracic surgery 11/2007; 84(4):1408-11. · 3.74 Impact Factor
  • Source
    P Sepúlveda, J Martinez-León, J M García-Verdugo
    [show abstract] [hide abstract]
    ABSTRACT: In the embryo, blood vessels and hematopoietic cells arise from the hemangioblast, a common precursor cell. Compelling evidence suggests that bone marrow from adult individuals contains endothelial cell precursors (EPCs), similar to embryonic hemangioblast. They are able to increase neovascularization of tissue after ischemia. Herein we have discussed the ontogeny of these cells, their phenotypes, and their isolation from various sources. We also have presented experimental studies indicating that EPCs are able to induce neovascularization and angiogenesis when transplanted into ischemic tissues. Furthermore, endogenous EPCs can be mobilized using factors that promote their homing to sites of tissue injury. We also have discussed the ongoing clinical trials using these cells to treat ischemic diseases.
    Transplantation Proceedings 10/2007; 39(7):2089-94. · 0.95 Impact Factor
  • Source
    [show abstract] [hide abstract]
    ABSTRACT: Most studies about prosthesis-patient mismatch (PPM) were conducted before the introduction of new high-performance prostheses. Nowadays, PPM could become unfrequent. Our aim was to study the impact of new prostheses on PPM in comparison with previous experience. Prosthetic Indexed Effective Orifice Area (EOAi) was estimated in two historical cohorts. Group A: 339 patients undergoing AVR from Mar 94-Nov 01. Group B: 404 operated on during the last three years when latest generation prostheses were implanted. Incidence, determinants of PPM and clinical results were studied. Moderate PPM (EOAi <or=0.85 cm(2)/m(2)) was present in 38% and 19% (respective groups). Mean EOAi increased from 1.02+/-0.29 cm(2)/m(2) to 1.11+/-0.27 cm(2)/m(2). 'Group B' and 'new prostheses' were protective. Thirty-day mortality was 3.8% and 4.7% with higher rate in patients with increased left ventricular mass index (LVMI), especially if PPM was present: 14.7 vs. 2.1% (P<0.05) in Group A; 25.0 vs. 4.8% (P<0.05) in Group B (PPM vs. no-PPM). LVMI regression was impaired in these patients. Moderate PPM was an independent predictor of late cardiac mortality (OR: 3.38, 95% CI: 1.37-8.31; P<0.01). PPM is a prognostic factor for late cardiac death. Its impact on early mortality is only relevant in patients with high LVMI. Its incidence has decreased with the use of new prostheses.
    Interactive Cardiovascular and Thoracic Surgery 08/2007; 6(4):462-9. · 1.11 Impact Factor
  • [show abstract] [hide abstract]
    ABSTRACT: We studied the participation of K(+) channels on the adrenergic responses in human saphenous veins as well as the intervention of dihydropyridine-sensitive Ca(2+) channels on modulation of adrenergic responses by K(+) channels blockade. Saphenous vein rings were obtained from 40 patients undergoing coronary artery bypass surgery. The vein rings were suspended in organ bath chambers for isometric recording of tension. Iberiotoxin (10(-7) mol/L), an inhibitor of large conductance Ca(2+)-activated K(+) channels, and charybdotoxin (10(-7) mol/L), an inhibitor of both large and intermediate conductance Ca(2+)-activated K(+) channels, enhanced the contractions elicited by electrical field stimulation and produced a leftward shift of the concentration-response curve to norepinephrine. In contrast, the inhibitor of small conductance Ca(2+)-activated K(+) channels apamin (10(-6) mol/L) did not modify the contractile response to electrical field stimulation or norepinephrine. In the presence of the dihydropyridine Ca(2+)-channel blocker nifedipine (10(-6) mol/L), iberiotoxin and charybdotoxin failed to enhance the contractile responses to electrical field stimulation and norepinephrine. The results suggest that large conductance Ca(2+)-activated K(+) channels are activated by stimulation with norepinephrine to counteract the adrenergic-induced contractions of human saphenous vein. Thus, inhibition of these channels increases significantly the contraction, an effect that appears to be mediated by an increase in Ca(2+) entry through L-type voltage-dependent Ca(2+) channels.
    American Journal of Hypertension 02/2007; 20(1):78-82. · 3.67 Impact Factor

Publication Stats

204 Citations
109.22 Total Impact Points


  • 2007–2013
    • Consorcio Hospital General Universitario de Valencia
      • Departamento de Cirugía Cardiaca
      Valencia, Valencia, Spain
  • 1997–2006
    • University of Valencia
      • • Departamento de Fisiología
      • • Departamento de Cirugía
      Valencia, Valencia, Spain
  • 2005
    • Hospital Clínico Universitario de Valencia
      Valenza, Valencia, Spain